Organic Compound, Light-Emitting Element, Light-Emitting Device, Electronic Device, and Lighting Device

ABSTRACT

An organic compound has a benzonaphthofuran skeleton and is represented by General Formula (G1). In General Formula (G1), A represents a pyrene skeleton. In the case where the pyrene skeleton has a substituent, the substituent is a diarylamino group including two substituted or unsubstituted aryl groups each having 6 to 13 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, an alkyl group having 1 to 7 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a substituted or unsubstituted polycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. The two aryl groups of the diarylamino group may be the same or different. In X1 represented by General Formula (G1-1), one of R6 and R7 is bonded to N in General Formula (G1), and the other of R6 and R7 represents an alkyl group having 1 to 7 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a substituted or unsubstituted polycyclic saturated hydrocarbon group having 7 to 10 carbon atoms.

This application is a continuation of copending U.S. application Ser.No. 16/609,284, filed on Oct. 29, 2019 which is a 371 of internationalapplication PCT/IB2018/052746 filed on Apr. 20, 2018 which are allincorporated herein by reference.

TECHNICAL FIELD

One embodiment of the present invention relates to an organic compound,a light-emitting element, a light-emitting device, an electronic device,and a lighting device. Note that one embodiment of the present inventionis not limited to the above technical field. That is, one embodiment ofthe present invention relates to an object, a method, a manufacturingmethod, or a driving method. One embodiment of the present inventionrelates to a process, a machine, manufacture, or a composition ofmatter. Specific examples include a semiconductor device, a displaydevice, a liquid crystal display device, and the like.

BACKGROUND ART

A light-emitting element including an electroluminescent (EL) layerbetween a pair of electrodes (also referred to as an organic EL element)has characteristics such as thinness, light weight, high-speed responseto input signals, and low power consumption; thus, a display includingsuch a light-emitting element has attracted attention as anext-generation flat panel display.

In a light-emitting element, voltage application between a pair ofelectrodes causes, in an EL layer, recombination of electrons and holesinjected from the electrodes, which brings a light-emitting substance(organic compound) contained in the EL layer into an excited state.Light is emitted when the light-emitting substance returns to the groundstate from the excited state. The excited state can be a singlet excitedstate (S*) and a triplet excited state (T*). Light emission from asinglet excited state is referred to as fluorescence, and light emissionfrom a triplet excited state is referred to as phosphorescence. Thestatistical generation ratio thereof in the light-emitting element isconsidered to be S*:T*=1:3. Since the spectrum of light emitted from alight-emitting substance depends on the light-emitting substance, theuse of different types of organic compounds as light-emitting substancesmakes it possible to obtain light-emitting elements which exhibitvarious colors.

In order to improve element characteristics of such a light-emittingelement, improvement of an element structure, development of a material,and the like have been actively carried out (see Patent Document 1, forexample).

REFERENCE

-   [Patent Document 1] Japanese Published Patent Application No.    2010-182699

DISCLOSURE OF INVENTION

In development of light-emitting elements, organic compounds used in thelight-emitting element are very important for improving thecharacteristics. Thus, an object of one embodiment of the presentinvention is to provide a novel organic compound. That is, an object isto provide a novel organic compound that is effective in improving theelement characteristics and reliability. Another object of oneembodiment of the present invention is to provide a novel organiccompound that can be used in a light-emitting element. Another object ofone embodiment of the present invention is to provide a novel organiccompound that can be used in an EL layer of a light-emitting element.Another object is to provide a highly efficient, highly reliable, andnovel light-emitting element using a novel organic compound of oneembodiment of the present invention. Another object is to provide anovel light-emitting element using a novel organic compound of oneembodiment of the present invention and emitting blue light with highcolor purity. Another object is to provide a novel light-emittingdevice, a novel electronic device, or a novel lighting device. Note thatthe description of these objects does not disturb the existence of otherobjects. In one embodiment of the present invention, there is notnecessarily a need to achieve all the objects. Other objects will beapparent from and can be derived from the description of thespecification, the drawings, the claims, and the like.

One embodiment of the present invention is an organic compound which hasa benzonaphthofuran skeleton and is represented by General Formula (G1)below.

In General Formula (G1), A represents a pyrene skeleton. In the casewhere the pyrene skeleton has a substituent, the substituent is adiarylamino group including two substituted or unsubstituted aryl groupseach having 6 to 13 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Thetwo aryl groups of the diarylamino group may be the same or different.In X¹ represented by General Formula (G1-1), one of R⁶ and R⁷ is bondedto N in General Formula (G1), and the other of R⁶ and R⁷ represents analkyl group having 1 to 7 carbon atoms, a substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Ar¹ represents a substituted orunsubstituted aryl group having 6 to 13 carbon atoms. Each of R¹ to R⁵and R⁸ to R¹⁰ independently represents hydrogen, an alkyl group having 1to 7 carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms. In addition, n represents 1 to 4, and in the case wheren is 2 or more, amine skeletons may be the same or different.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G2) below.

In General Formula (G2), A represents a substituted or unsubstitutedpyrene skeleton. X¹ and X² represented by General Formula (G2-1) areindependent of each other. One of R⁶ and R⁷ is bonded to N in GeneralFormula (G2), and the other of R⁶ and R⁷ represents an alkyl grouphaving 1 to 7 carbon atoms, a substituted or unsubstituted monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Each of Ar¹ and Ar² independentlyrepresents a substituted or unsubstituted aryl group having 6 to 13carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰ independently representshydrogen, an alkyl group having 1 to 7 carbon atoms, a substituted orunsubstituted monocyclic saturated hydrocarbon group having 3 to 20carbon atoms, a substituted or unsubstituted polycyclic saturatedhydrocarbon group having 7 to 10 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

In each of the above embodiments, the other of R⁶ and R⁷ is preferably amonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms. Themonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms isfurther preferably a cyclohexyl group.

Another embodiment of the present invention is as follows. In GeneralFormula (G2), A represents a substituted or unsubstituted pyreneskeleton. X¹ and X² represented by General Formula (G2-1) areindependent of each other. One of R⁶ and R⁷ is bonded to N in GeneralFormula (G2), and the other of R⁶ and R⁷ represents a trialkylsilylgroup having 3 to 18 carbon atoms or a substituted or unsubstitutedtriarylsilyl group having 18 to 30 carbon atoms. Each of Ar¹ and Ar²independently represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G3) below.

In General Formula (G3), A represents a substituted or unsubstitutedpyrene skeleton. R¹⁶ and R²⁶ each represent an alkyl group having 1 to 7carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms. Each of R¹¹ to R¹⁵, R¹⁷ to R¹⁹, R²¹ to R²⁵, and R²⁷ to R²⁹independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the above embodiment, R¹⁶ and R²⁶ are each preferably a monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms. The monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms is furtherpreferably a cyclohexyl group.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G4) below.

In General Formula (G4), at least one of R³¹, R³³, R³⁵, and R³⁸ has agroup represented by General Formula (G4-1). In the case where two ormore of R³¹, R³³, R³⁵, and R³⁸ have the group represented by GeneralFormula (G4-1), they may have the same structure or differentstructures. R⁶ represents an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Eachof all those which, out of R³¹ to R⁴⁰, do not have the group representedby General Formula (G4-1) and R¹ to R⁵ and R⁸ to R¹⁰ independentlyrepresents hydrogen, an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, a substituted or unsubstituted polycyclicsaturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In each of the above embodiments, R⁶ is preferably a monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms. The monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms is furtherpreferably a cyclohexyl group.

The above-described organic compound of one embodiment of the presentinvention has a structure in which an amine is bonded to the pyreneskeleton and the amine and the benzonaphthofuran skeleton are bonded.The amine is bonded to one of 6- and 8-positions of thebenzonaphthofuran skeleton, and the other of the 6- and 8-positions ofthe benzonaphthofuran skeleton (the position to which the amine is notbonded) has a specific substituent, i.e., an alkyl group having 1 to 7carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms. Note that such a structure enables the emission spectrumto be narrowed. The narrowed emission spectrum can improve the elementcharacteristics of, for example, a top-emission light-emitting elementhaving a microcavity structure. In addition, the use of such a materialin manufacturing a light-emitting element can improve the reliability ofthe light-emitting element. Furthermore, such a structure improves thesublimability of a compound and can therefore reduce decomposition ofthe compound at the time of evaporation. Suppression of decomposition atthe time of evaporation makes it possible to provide a highly reliablelight-emitting element. It is preferable that the above-describedspecific substituent be a monocyclic saturated hydrocarbon group having3 to 20 carbon atoms because the above effect is significant and theyield of synthesis is high. It is particularly preferable that thespecific substituent be a cyclohexyl group.

Another embodiment of the present invention is an organic compoundrepresented by Structural Formula (100) or Structural Formula (101).

Another embodiment of the present invention is a light-emitting elementcontaining the organic compound of one embodiment of the presentinvention. Note that the present invention also includes alight-emitting element containing a host material in addition to theabove organic compound.

Another embodiment of the present invention is a light-emitting elementcontaining the organic compound of one embodiment of the presentinvention. Note that the present invention also includes alight-emitting element in which an EL layer provided between a pair ofelectrodes or a light-emitting layer included in the EL layer containsthe organic compound of one embodiment of the present invention. Inaddition to the above light-emitting elements, a light-emitting deviceincluding a transistor, a substrate, or the like is also included in thescope of the invention. Furthermore, in addition to the light-emittingdevice, an electronic device and a lighting device that include amicrophone, a camera, an operation button, an external connectionportion, a housing, a cover, a support, a speaker, or the like are alsoincluded in the scope of the invention.

One embodiment of the present invention includes, in its scope, alight-emitting device including a light-emitting element, and a lightingdevice including the light-emitting device. Accordingly, thelight-emitting device in this specification refers to an image displaydevice and a light source (including a lighting device). In addition,the light-emitting device includes, in its category, all of a module inwhich a connector such as a flexible printed circuit (FPC) or a tapecarrier package (TCP) is connected to a light-emitting device, a modulein which a printed wiring board is provided at the end of a TCP, and amodule in which an integrated circuit (IC) is directly mounted on alight-emitting element by a chip on glass (COG) method.

According to one embodiment of the present invention, a novel organiccompound can be provided. In other words, a novel organic compound thatis effective in improving the element characteristics can be provided.According to one embodiment of the present invention, a novel organiccompound that can be used in a light-emitting element can be provided.According to one embodiment of the present invention, a novel organiccompound that can be used in an EL layer of a light-emitting element canbe provided. According to one embodiment of the present invention, ahighly efficient, highly reliable, and novel light-emitting elementusing a novel organic compound of one embodiment of the presentinvention can be provided. According to one embodiment of the presentinvention, a novel light-emitting element using a novel organic compoundof one embodiment of the present invention and emitting blue light withhigh color purity can be provided. In addition, a novel light-emittingdevice, a novel electronic device, or a novel lighting device can beprovided. Note that the description of these effects does not disturbthe existence of other effects. In one embodiment of the presentinvention, there is not necessarily a need to achieve all the effects.Other effects will be apparent from and can be derived from thedescription of the specification, the drawings, the claims, and thelike.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1E illustrate structures of light-emitting elements.

FIGS. 2A to 2C illustrate light-emitting devices.

FIGS. 3A and 3B illustrate a light-emitting device.

FIGS. 4A to 4G illustrate electronic devices.

FIGS. 5A to 5C illustrate an electronic device.

FIGS. 6A and 6B illustrate an automobile.

FIGS. 7A to 7D illustrate lighting devices.

FIG. 8 illustrates lighting devices.

FIGS. 9A to 9C show ¹H-NMR charts ofN-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine.

FIGS. 10A to 10C show ¹H-NMR charts of an organic compound representedby Structural Formula (100).

FIGS. 11A and 11B each show an ultraviolet-visible absorption spectrumand an emission spectrum of the organic compound represented byStructural Formula (100).

FIGS. 12A to 12C show ¹H-NMR charts ofN-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine.

FIGS. 13A to 13C show ¹H-NMR charts of an organic compound representedby Structural Formula (101).

FIGS. 14A and 14B each show an ultraviolet-visible absorption spectrumand an emission spectrum of the organic compound represented byStructural Formula (101).

FIGS. 15A to 15C show ¹H-NMR charts ofN-phenyl-6-isopropylbenzo[b]naphtho[1,2-d]furan-8-amine.

FIGS. 16A to 16C show ¹H-NMR charts of an organic compound representedby Structural Formula (116).

FIG. 17 illustrates a light-emitting element.

FIG. 18 shows current density-luminance characteristics of alight-emitting element 1 and a comparative light-emitting element 2.

FIG. 19 shows voltage-luminance characteristics of the light-emittingelement 1 and the comparative light-emitting element 2.

FIG. 20 shows luminance-current efficiency characteristics of thelight-emitting element 1 and the comparative light-emitting element 2.

FIG. 21 shows voltage-current characteristics of the light-emittingelement 1 and the comparative light-emitting element 2.

FIG. 22 shows emission spectra of the light-emitting element 1 and thecomparative light-emitting element 2.

FIG. 23 shows reliability of the light-emitting element 1 and thecomparative light-emitting element 2.

FIGS. 24A to 24C show ¹H-NMR charts of an organic compound representedby Structural Formula (118).

FIGS. 25A and 25B each show an ultraviolet-visible absorption spectrumand an emission spectrum of the organic compound represented byStructural Formula (118).

FIGS. 26A to 26C show ¹H-NMR charts of an organic compound representedby Structural Formula (117).

FIGS. 27A and 27B each show an ultraviolet-visible absorption spectrumand an emission spectrum of the organic compound represented byStructural Formula (117).

FIGS. 28A to 28C show ¹H-NMR charts of an organic compound representedby Structural Formula (145).

FIGS. 29A and 29B each show an ultraviolet-visible absorption spectrumand an emission spectrum of the organic compound represented byStructural Formula (145).

FIGS. 30A to 30C show ¹H-NMR charts of an organic compound representedby Structural Formula (142).

FIGS. 31A and 31B each show an ultraviolet-visible absorption spectrumand an emission spectrum of the organic compound represented byStructural Formula (142).

FIGS. 32A to 32C show ¹H-NMR charts of ch-1,6BnfAPrn-02.

FIGS. 33A and 33B each show an ultraviolet-visible absorption spectrumand an emission spectrum of ch-1,6BnfAPrn-02.

FIG. 34 shows current density-luminance characteristics of alight-emitting element 3, a light-emitting element 4, and alight-emitting element 5.

FIG. 35 shows voltage-luminance characteristics of the light-emittingelement 3, the light-emitting element 4, and the light-emitting element5.

FIG. 36 shows luminance-current efficiency characteristics of thelight-emitting element 3, the light-emitting element 4, and thelight-emitting element 5.

FIG. 37 shows voltage-current characteristics of the light-emittingelement 3, the light-emitting element 4, and the light-emitting element5.

FIG. 38 shows emission spectra of the light-emitting element 3, thelight-emitting element 4, and the light-emitting element 5.

FIG. 39 shows current density-luminance characteristics of alight-emitting element 6 and a comparative light-emitting element 7.

FIG. 40 shows voltage-luminance characteristics of the light-emittingelement 6 and the comparative light-emitting element 7.

FIG. 41 shows luminance-current efficiency characteristics of thelight-emitting element 6 and the comparative light-emitting element 7.

FIG. 42 shows voltage-current characteristics of the light-emittingelement 6 and the comparative light-emitting element 7.

FIG. 43 shows emission spectra of the light-emitting element 6 and thecomparative light-emitting element 7.

FIG. 44 shows the chromaticities of the light-emitting element 6 and thecomparative light-emitting element 7.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below withreference to the drawings. Note that the present invention is notlimited to the following description, and the modes and details of thepresent invention can be modified in various ways without departing fromthe spirit and scope of the present invention. Therefore, the presentinvention should not be construed as being limited to the description inthe following embodiments.

Note that the position, size, range, or the like of each componentillustrated in drawings and the like is not accurately represented insome cases for easy understanding. Therefore, the disclosed invention isnot necessarily limited to the position, size, range, or the likedisclosed in the drawings and the like.

In the description of modes of the present invention with reference tothe drawings in this specification and the like, the same components indifferent diagrams are commonly denoted by the same reference numeral.

Embodiment 1

In this embodiment, organic compounds each of which is one embodiment ofthe present invention are described.

Note that an organic compound described in this embodiment has astructure which has a benzonaphthofuran skeleton and is represented byGeneral Formula (G1) below.

In General Formula (G1), A represents a pyrene skeleton. In the casewhere the pyrene skeleton has a substituent, the substituent is adiarylamino group including two substituted or unsubstituted aryl groupseach having 6 to 13 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Thetwo aryl groups of the diarylamino group may be the same or different.In X¹ represented by General Formula (G1-1), one of R⁶ and R⁷ is bondedto N in General Formula (G1), and the other of R⁶ and R⁷ represents analkyl group having 1 to 7 carbon atoms, a substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Ar¹ represents a substituted orunsubstituted aryl group having 6 to 13 carbon atoms. Each of R¹ to R⁵and R⁸ to R¹⁰ independently represents hydrogen, an alkyl group having 1to 7 carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms. In addition, n represents 1 to 4, and in the case wheren is 2 or more, amine skeletons may be the same or different.

An organic compound described in this embodiment is represented byGeneral Formula (G2) below.

In General Formula (G2), A represents a substituted or unsubstitutedpyrene skeleton. X¹ and X² represented by General Formula (G2-1) areindependent of each other. One of R⁶ and R⁷ is bonded to N in GeneralFormula (G2), and the other of R⁶ and R⁷ represents an alkyl grouphaving 1 to 7 carbon atoms, a substituted or unsubstituted monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Each of Ar¹ and Ar² independentlyrepresents a substituted or unsubstituted aryl group having 6 to 13carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰ independently representshydrogen, an alkyl group having 1 to 7 carbon atoms, a substituted orunsubstituted monocyclic saturated hydrocarbon group having 3 to 20carbon atoms, a substituted or unsubstituted polycyclic saturatedhydrocarbon group having 7 to 10 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

In each of the above structures, the other of R⁶ and R⁷ is preferably amonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms. Themonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms isfurther preferably a cyclohexyl group.

Another embodiment of the present invention is as follows. In GeneralFormula (G2), A represents a substituted or unsubstituted pyreneskeleton. X¹ and X² represented by General Formula (G2-1) areindependent of each other. One of R⁶ and R⁷ is bonded to N in GeneralFormula (G2), and the other of R⁶ and R⁷ represents a trialkylsilylgroup having 3 to 18 carbon atoms or a substituted or unsubstitutedtriarylsilyl group having 18 to 30 carbon atoms. Each of Ar¹ and Ar²independently represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the case where one of R⁶ and R⁷ in General Formula (G2-1) is atrialkylsilyl group having 3 to 18 carbon atoms, examples of thetrialkylsilyl group include a trimethylsilyl group, a triethylsilylgroup, a tri(n-propyl)silyl group, a triisopropylsilyl group, atri(n-butyl)silyl group, a tri(sec-butyl)silyl group, a triisobutylsilylgroup, a tri(tert-butyl)silyl group, a tri(n-pentyl)silyl group, atriisopenthylsilyl group, a tri(sec-pentyl)silyl group, atri(tert-pentyl)silyl group, a trineopentylsilyl group, atri(n-hexyl)silyl group, a triisohexylsilyl group, a tri(sec-hexyl)silylgroup, a tri(tert-hexyl)silyl group, a trineohexylsilyl group, atri(3-methylpentyl)silyl group, a tri(2-methylpentyl)silyl group, atri(2-ethylbutyl)silyl group, a tri(1,2-dimethylbutyl)silyl group, atri(2,3-dimethylbutyl)silyl group, and the like. In the case where oneof R⁶ and R⁷ is a substituted or unsubstituted triarylsilyl group having18 to 30 carbon atoms, examples of the triarylsilyl group include atriphenylsilyl group, a tri(1-naphthyl)silyl group, atri(2-naphthyl)silyl group, a tri(ortho-tolyl)silyl group, atri(meta-tolyl)silyl group, a tri(para-tolyl)silyl group, atrimesitylsilyl group, a tri(para-tert-butylphenyl)silyl group, and thelike.

An organic compound described in this embodiment is represented byGeneral Formula (G3) below.

In General Formula (G3), A represents a substituted or unsubstitutedpyrene skeleton. R¹⁶ and R²⁶ each represent an alkyl group having 1 to 7carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms. Each of R¹¹ to R¹⁵, R¹⁷ to R¹⁹, R²¹ to R²⁵, and R²⁷ to R²⁹independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the above structure, R¹⁶ and R²⁶ are each preferably a monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms. The monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms is furtherpreferably a cyclohexyl group.

An organic compound described in this embodiment is represented byGeneral Formula (G4) below.

In General Formula (G4), at least one of R³¹, R³³, R³⁵, and R³⁸ has agroup represented by General Formula (G4-1). In the case where two ormore of R³¹, R³³, R³⁵, and R³⁸ have the group represented by GeneralFormula (G4-1), they may have the same structure or differentstructures. R⁶ represents an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Eachof all those which, out of R³¹ to R⁴⁰, do not have the group representedby General Formula (G4-1) and R¹ to R⁵ and R⁸ to R¹⁰ independentlyrepresents hydrogen, an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, a substituted or unsubstituted polycyclicsaturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In each of the above structures, R⁶ is preferably a monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms. The monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms is further preferably acyclohexyl group.

In the case where the pyrene skeleton represented by A in each ofGeneral Formulae (G1) to (G3) has a substituent, examples of thesubstituent include a diarylamino group including two substituted orunsubstituted aryl groups each having 6 to 13 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms, analkyl group having 1 to 7 carbon atoms, a substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, anda substituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Specific examples of the substituentinclude those which are represented by Structural Formulae (01) to (58)below.

In any of General Formulae (G1) to (G3), in the case where thediarylamino group including two substituted or unsubstituted aryl groupseach having 6 to 13 carbon atoms, the substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, the substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, orthe substituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms has a substituent, examples of thesubstituent include an alkyl group having 1 to 7 carbon atoms, such as amethyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, apentyl group, or a hexyl group; a cycloalkyl group having 5 to 7 carbonatoms, such as a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, or a 8,9,10-trinorbornanyl group; an aryl group having 6 to 12carbon atoms, such as a phenyl group, a naphthyl group, or a biphenylgroup; and the like.

Specific examples of the monocyclic saturated hydrocarbon group having 3to 20 carbon atoms in any of General Formulae (G1) to (G4) include acyclopropyl group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a 2-methylcyclohexyl group, a cyclooctyl group, acyclononyl group, a cyclodecyl group, a cycloicosyl group, and the like.

Specific examples of the polycyclic saturated hydrocarbon group having 7to 10 carbon atoms in any of General Formulae (G1) to (G4) include a8,9,10-trinorbornanyl group, a decahydronaphthyl group, an adamantylgroup, and the like.

Specific examples of the aryl group having 6 to 13 carbon atoms in anyof General Formulae (G1) to (G4) include a phenyl group, an o-tolylgroup, an m-tolyl group, a p-tolyl group, a mesityl group, an o-biphenylgroup, an m-biphenyl group, a p-biphenyl group, a 1-naphthyl group, a2-naphthyl group, a fluorenyl group, a 9,9-dimethylfluorenyl group, andthe like.

Specific examples of the alkyl group having 1 to 7 carbon atoms in anyof General Formulae (G1) to (G4) include a methyl group, an ethyl group,a propyl group, an isopropyl group, a butyl group, a sec-butyl group, anisobutyl group, a tert-butyl group, a pentyl group, an isopentyl group,a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexylgroup, an isohexyl group, a 3-methylpentyl group, a 2-methylpentylgroup, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, a2,3-dimethylbutyl group, an n-heptyl group, and the like.

In addition, the other of R⁶ and R⁷ in General Formula (G1-1) or (G2-1)or R⁶ in General Formula (G4-1) represents an alkyl group having 1 to 7carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms, and specific examples thereof include those which arerepresented by Structural Formulae (02) to (23) below.

In addition, Ar¹ in General Formula (G1), Ar¹ and Ar² in General Formula(G2), Ar¹ and Ar² in General Formula (G3), or Ar² in General Formula(G4) represent(s) a substituted or unsubstituted aryl group having 6 to13 carbon atoms, and specific examples thereof include those which arerepresented by Structural Formulae (24) to (37) below.

In addition, each of R¹ to R⁵ and R⁸ to R¹⁰ in any of General Formulae(G1-1), (G2-1), and (G4-1) independently represents hydrogen, an alkylgroup having 1 to 7 carbon atoms, a substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms, or a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, and specific examples thereof includethose which are represented by Structural Formulae (01) to (32) below.

The above-described organic compound of one embodiment of the presentinvention, which is represented by any of General Formulae (G1) to (G4),has a structure in which an amine is bonded to the pyrene skeleton andthe amine and the benzonaphthofuran skeleton are bonded. The amine isbonded to one of 6- and 8-positions of the benzonaphthofuran skeleton,and the other of the 6- and 8-positions of the benzonaphthofuranskeleton (the position to which the amine is not bonded) has a specificsubstituent, i.e., an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Notethat such a structure enables the emission spectrum to be narrowed. Thenarrowed emission spectrum can improve the element characteristics of,for example, a top-emission light-emitting element having a microcavitystructure. In addition, the use of such a material in manufacturing alight-emitting element can improve the reliability of the light-emittingelement. Furthermore, such a structure improves the sublimability of acompound and can therefore reduce decomposition of the compound at thetime of evaporation. Suppression of decomposition at the time ofevaporation makes it possible to provide a highly reliablelight-emitting element. It is preferable that the above-describedspecific substituent be a monocyclic saturated hydrocarbon group having3 to 20 carbon atoms because the above effect is significant and theyield of synthesis is high. It is particularly preferable that thespecific substituent be a cyclohexyl group.

Next, specific structural formulae of the above-described organiccompounds, each of which is one embodiment of the present invention, areshown below. Note that the present invention is not limited to theseformulae.

Note that the organic compounds represented by Structural Formulae (100)to (145) are examples of the organic compound represented by any ofGeneral Formulae (G1) to (G4). The organic compound of one embodiment ofthe present invention is not limited thereto.

Next, an example of a method for synthesizing the organic compound whichis one embodiment of the present invention and is represented by GeneralFormula (G1) will be described.

<<Method for Synthesizing Organic Compound Represented by GeneralFormula (G1)>>

An example of a method for synthesizing the organic compound representedby General Formula (G1) will be described.

In General Formula (G1), A represents a pyrene skeleton. In the casewhere the pyrene skeleton has a substituent, the substituent is adiarylamino group including two substituted or unsubstituted aryl groupseach having 6 to 13 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Thetwo aryl groups of the diarylamino group may be the same or different.In X¹ represented by General Formula (G1-1), one of R⁶ and R⁷ is bondedto N in General Formula (G1), and the other of R⁶ and R⁷ represents analkyl group having 1 to 7 carbon atoms, a substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Ar¹ represents a substituted orunsubstituted aryl group having 6 to 13 carbon atoms. Each of R¹ to R⁵and R⁸ to R¹⁰ independently represents hydrogen, an alkyl group having 1to 7 carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms. In addition, n represents 1 to 4, and in the case wheren is 2 or more, amine skeletons may be the same or different.

<Method for Synthesizing Organic Compound Represented by General Formula(G1)>

The organic compound represented by General Formula (G1) can besynthesized by a synthesis method in which any of a variety of reactionsis used. For example, the organic compound can be synthesized bySynthesis Schemes (A-1) and (A-2) below. First, an arylamine (acompound 1) and a halogenated aryl (a compound 2) are coupled, whereby abenzo[b]naphtho[1,2-d]furanylamine compound (a compound 3) is obtained.Next, the benzo[b]naphtho[1,2-d]furanylamine compound (the compound 3)and a pyrene compound (a compound 4) are coupled, whereby the organiccompound represented by General Formula (G1) can be obtained.

In Synthesis Schemes (A-1) and (A-2), A represents a pyrene skeleton. Inthe case where the pyrene skeleton has a substituent, the substituent isa diarylamino group including two substituted or unsubstituted arylgroups each having 6 to 13 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 13 carbon atoms, an alkyl group having 1 to 7carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms. The two aryl groups of the diarylamino group may be thesame or different. In X¹ represented by General Formula (G1-1), one ofR⁶ and R⁷ is bonded to N in General Formula (G1), and the other of R⁶and R⁷ represents an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Ar¹represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰ independently representshydrogen, an alkyl group having 1 to 7 carbon atoms, a substituted orunsubstituted monocyclic saturated hydrocarbon group having 3 to 20carbon atoms, a substituted or unsubstituted polycyclic saturatedhydrocarbon group having 7 to 10 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms. In addition, nrepresents 1 to 4, and in the case where n is 2 or more, amine skeletonsmay be the same or different.

In the case where a Buchwald-Hartwig reaction using a palladium catalystis employed in Synthesis Schemes (A-1) and (A-2), X¹⁰ represents ahalogen group or a triflate group. As the halogen, iodine, bromine, orchlorine is preferable. In the case where n is 2 or more and differentamino groups are bonded to the pyrene skeleton, different halogens arepreferably used as X¹⁰ to selectively react with the amino groups. Inthe reaction, a palladium compound such asbis(dibenzylideneacetone)palladium(0) or palladium(II) acetate and aligand such as tri(tert-butyl)phosphine, tri(n-hexyl)phosphine,tricyclohexylphosphine, di(1-adamantyl)-n-butylphosphine, or2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl can be used. Inaddition, an organic base such as sodium tert-butoxide, an inorganicbase such as potassium carbonate, cesium carbonate, or sodium carbonate,or the like can be used. Furthermore, toluene, xylene, benzene,tetrahydrofuran, dioxane, or the like can be used as a solvent. Reagentsthat can be used in the reaction are not limited thereto.

The reaction employed in Synthesis Schemes (A-1) and (A-2) is notlimited to the Buchwald-Hartwig reaction. A Migita-Kosugi-Stillecoupling reaction using an organotin compound, a coupling reaction usinga Grignard reagent, an Ullmann reaction using copper or a coppercompound, or the like can be used.

Note that the benzo[b]naphtho[1,2-d]furanylamine compound (the compound3) obtained by coupling of the arylamine (the compound 1) and thehalogenated aryl (the compound 2) in Synthesis Scheme (A-1) is acompound obtained as an intermediate at the time of synthesizing theorganic compound of one embodiment of the present invention and isanother organic compound of one embodiment of the present invention.

Specific examples of the compound 3 shown in Synthesis Scheme (A-1)include those which are represented by Structural Formulae (201) to(227) below.

Next, an example of a method for synthesizing the organic compound whichis one embodiment of the present invention and is represented by GeneralFormula (G2) will be described.

<Method for Synthesizing Organic Compound Represented by General Formula(G2)>

An example of a method for synthesizing the organic compound representedby General Formula (G2) will be described.

In General Formula (G2), A represents a substituted or unsubstitutedpyrene skeleton. X¹ and X² represented by General Formula (G2-1) areindependent of each other. One of R⁶ and R⁷ is bonded to N in GeneralFormula (G2), and the other of R⁶ and R⁷ represents an alkyl grouphaving 1 to 7 carbon atoms, a substituted or unsubstituted monocyclicsaturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Each of Ar¹ and Ar² independentlyrepresents a substituted or unsubstituted aryl group having 6 to 13carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰ independently representshydrogen, an alkyl group having 1 to 7 carbon atoms, a substituted orunsubstituted monocyclic saturated hydrocarbon group having 3 to 20carbon atoms, a substituted or unsubstituted polycyclic saturatedhydrocarbon group having 7 to 10 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

Alternatively, in General Formula (G2), A represents a substituted orunsubstituted pyrene skeleton. X¹ and X² represented by General Formula(G2-1) are independent of each other. One of R⁶ and R⁷ is bonded to N inGeneral Formula (G2), and the other of R⁶ and R⁷ represents atrialkylsilyl group having 3 to 18 carbon atoms or a substituted orunsubstituted triarylsilyl group having 18 to 30 carbon atoms. Each ofAr¹ and Ar² independently represents a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

<Method for Synthesizing Organic Compound Represented by General Formula(G2)>

The organic compound represented by General Formula (G2) can besynthesized by a synthesis method in which any of a variety of reactionsis used. For example, the organic compound can be synthesized bySynthesis Schemes (B-1) and (B-2) below. First, a pyrene compound (acompound 5), an arylamine (a compound 6), and an arylamine (a compound7) are coupled, whereby a pyrenediamine compound (a compound 8) isobtained. Next, the pyrenediamine compound (the compound 8), thehalogenated aryl (the compound 2), and a halogenated aryl (a compound 9)are coupled, whereby the organic compound represented by General Formula(G2) can be obtained.

In Synthesis Schemes (B-1) and (B-2), A represents a pyrene skeleton. Inthe case where the pyrene skeleton has a substituent, the substituent isa diarylamino group including two substituted or unsubstituted arylgroups each having 6 to 13 carbon atoms, a substituted or unsubstitutedaryl group having 6 to 13 carbon atoms, an alkyl group having 1 to 7carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms. The two aryl groups of the diarylamino group may be thesame or different. In X¹ represented by General Formula (G2-1), one ofR⁶ and R⁷ is bonded to N in General Formula (G2), and the other of R⁶and R⁷ represents an alkyl group having 1 to 7 carbon atoms, asubstituted or unsubstituted monocyclic saturated hydrocarbon grouphaving 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Ar¹represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰ independently representshydrogen, an alkyl group having 1 to 7 carbon atoms, a substituted orunsubstituted monocyclic saturated hydrocarbon group having 3 to 20carbon atoms, a substituted or unsubstituted polycyclic saturatedhydrocarbon group having 7 to 10 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

Alternatively, in Synthesis Scheme (B-2), A represents a substituted orunsubstituted pyrene skeleton. X¹ and X² represented by General Formula(G2-1) are independent of each other. One of R⁶ and R⁷ is bonded to N inGeneral Formula (G2), and the other of R⁶ and R⁷ represents atrialkylsilyl group having 3 to 18 carbon atoms or a substituted orunsubstituted triarylsilyl group having 18 to 30 carbon atoms. Each ofAr¹ and Ar² independently represents a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the case where a Buchwald-Hartwig reaction using a palladium catalystis employed in Synthesis Schemes (B-1) and (B-2), X¹¹ to X¹⁴ represent ahalogen group or a triflate group. As the halogen, iodine, bromine, orchlorine is preferable. In the reaction, a palladium compound such asbis(dibenzylideneacetone)palladium(0) or palladium(II) acetate and aligand such as tri(tert-butyl)phosphine, tri(n-hexyl)phosphine,tricyclohexylphosphine, di(1-adamantyl)-n-butylphosphine, or2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl can be used. Inaddition, an organic base such as sodium tert-butoxide, an inorganicbase such as potassium carbonate, cesium carbonate, or sodium carbonate,or the like can be used. Furthermore, toluene, xylene, benzene,tetrahydrofuran, dioxane, or the like can be used as a solvent. Reagentsthat can be used in the reaction are not limited thereto.

The reaction employed in Synthesis Schemes (B-1) and (B-2) is notlimited to the Buchwald-Hartwig reaction. A Migita-Kosugi-Stillecoupling reaction using an organotin compound, a coupling reaction usinga Grignard reagent, an Ullmann reaction using copper or a coppercompound, or the like can be used.

In the case where the compound 6 and the compound 7 have differentstructures in Synthesis Scheme (B-1), it is preferable that the compound5 and the compound 6 be reacted first to form a coupling product andthen the coupling product and the compound 7 be reacted. In the casewhere the compound 5 is reacted with the compound 6 and the compound 7one by one, it is preferable that the compound 5 be a dihalogen compoundand X¹¹ and X¹² be different halogens and selectively subjected toamination reactions one by one.

Furthermore, in the case where the compound 2 and the compound 9 havedifferent structures in Synthesis Scheme (B-2), it is preferable thatthe compound 8 and the compound 2 be reacted first to form a couplingproduct and then the coupling product and the compound 9 be reacted.

Next, an example of a method for synthesizing an organic compound whichis one embodiment of the present invention and is represented by GeneralFormula (G2′) will be described. In the organic compound represented byGeneral Formula (G2′), X¹ and X² in General Formula (G2) have the samestructure.

<Method for Synthesizing Organic Compound Represented by General Formula(G2′)>

An example of a method for synthesizing the organic compound representedby General Formula (G2′) will be described.

In General Formula (G2′), A represents a substituted or unsubstitutedpyrene skeleton. One of R⁶ and R⁷ is bonded to N in General Formula(G2′), and the other of R⁶ and R⁷ represents an alkyl group having 1 to7 carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, or a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms. Ar¹ represents a substituted or unsubstituted aryl grouphaving 6 to 13 carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

Alternatively, in General Formula (G2′), A represents a substituted orunsubstituted pyrene skeleton. One of R⁶ and R⁷ is bonded to N inGeneral Formula (G2′), and the other of R⁶ and R⁷ represents atrialkylsilyl group having 3 to 18 carbon atoms or a substituted orunsubstituted triarylsilyl group having 18 to 30 carbon atoms. Each ofAr¹ and Ar² independently represents a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰independently represents hydrogen, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 13 carbon atoms.

<Method for Synthesizing Organic Compound Represented by General Formula(G2′)>

The organic compound represented by General Formula (G2′) can besynthesized by a synthesis method in which any of a variety of reactionsis used. For example, the organic compound can be synthesized bySynthesis Scheme (C-1) below. That is, the pyrene compound (the compound5) and the benzo[b]naphtho[1,2-d]furanylamine compound (the compound 3)are coupled, whereby the organic compound represented by General Formula(G2′) can be obtained.

In Synthesis Scheme (C-1), A represents a pyrene skeleton. In the casewhere the pyrene skeleton has a substituent, the substituent is adiarylamino group including two substituted or unsubstituted aryl groupseach having 6 to 13 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 13 carbon atoms, an alkyl group having 1 to 7 carbonatoms, a substituted or unsubstituted monocyclic saturated hydrocarbongroup having 3 to 20 carbon atoms, or a substituted or unsubstitutedpolycyclic saturated hydrocarbon group having 7 to 10 carbon atoms. Thetwo aryl groups of the diarylamino group may be the same or different.In X¹ represented by General Formula (G2′-1), one of R⁶ and R⁷ is bondedto N in General Formula (G2′), and the other of R⁶ and R⁷ represents analkyl group having 1 to 7 carbon atoms, a substituted or unsubstitutedmonocyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or asubstituted or unsubstituted polycyclic saturated hydrocarbon grouphaving 7 to 10 carbon atoms. Ar¹ represents a substituted orunsubstituted aryl group having 6 to 13 carbon atoms. Each of R¹ to R⁵and R⁸ to R¹⁰ independently represents hydrogen, an alkyl group having 1to 7 carbon atoms, a substituted or unsubstituted monocyclic saturatedhydrocarbon group having 3 to 20 carbon atoms, a substituted orunsubstituted polycyclic saturated hydrocarbon group having 7 to 10carbon atoms, or a substituted or unsubstituted aryl group having 6 to13 carbon atoms.

Alternatively, in Synthesis Scheme (C-1), A represents a substituted orunsubstituted pyrene skeleton. One of R⁶ and R⁷ is bonded to N inGeneral Formula (G2′), and the other of R⁶ and R⁷ represents atrialkylsilyl group having 3 to 18 carbon atoms or a substituted orunsubstituted triarylsilyl group having 18 to 30 carbon atoms. Ar¹represents a substituted or unsubstituted aryl group having 6 to 13carbon atoms. Each of R¹ to R⁵ and R⁸ to R¹⁰ independently representshydrogen, an alkyl group having 1 to 7 carbon atoms, a substituted orunsubstituted monocyclic saturated hydrocarbon group having 3 to 20carbon atoms, a substituted or unsubstituted polycyclic saturatedhydrocarbon group having 7 to 10 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 13 carbon atoms.

In the case where a Buchwald-Hartwig reaction using a palladium catalystis employed in Synthesis Scheme (C-1), X¹¹ and X¹² represent a halogengroup or a triflate group. As the halogen, iodine, bromine, or chlorineis preferable. To bond the same amino groups to the pyrene skeleton, itis preferable that X¹¹ and X¹² be the same. In the reaction, a palladiumcompound such as bis(dibenzylideneacetone)palladium(0) or palladium(II)acetate and a ligand such as tri(tert-butyl)phosphine,tri(n-hexyl)phosphine, tricyclohexylphosphine,di(1-adamantyl)-n-butylphosphine, or2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl can be used. Inaddition, an organic base such as sodium tert-butoxide, an inorganicbase such as potassium carbonate, cesium carbonate, or sodium carbonate,or the like can be used. Furthermore, toluene, xylene, benzene,tetrahydrofuran, dioxane, or the like can be used as a solvent. Reagentsthat can be used in the reaction are not limited thereto.

The reaction employed in Synthesis Scheme (C-1) is not limited to theBuchwald-Hartwig reaction. A Migita-Kosugi-Stille coupling reactionusing an organotin compound, a coupling reaction using a Grignardreagent, an Ullmann reaction using copper or a copper compound, or thelike can be used.

The above is the description of methods for synthesizing the organiccompounds which are embodiments of the present invention and arerepresented by General Formulae (G1), (G2), and (G2′); however, thepresent invention is not limited thereto, and another synthesis methodmay be employed.

With the use of the organic compound of one embodiment of the presentinvention, a light-emitting element, a light-emitting device, anelectronic device, or a lighting device with high emission efficiencycan be obtained. In addition, alight-emitting element, alight-emittingdevice, an electronic device, or a lighting device with low powerconsumption can be obtained.

In this embodiment, embodiments of the present invention have beendescribed. Other embodiments of the present invention are described inthe other embodiments. Note that embodiments of the present inventionare not limited thereto. In other words, since various embodiments ofthe invention are described in this embodiment and the otherembodiments, embodiments of the present invention are not limited toparticular embodiments.

The structures described in this embodiment can be combined with any ofthe structures described in the other embodiments as appropriate.

Embodiment 2

In this embodiment, a light-emitting element including any of theorganic compounds described in Embodiment 1 is described with referenceto FIGS. 1A to 1E.

<<Basic Structure of Light-Emitting Element>>

A basic structure of a light-emitting element will be described. FIG. 1Aillustrates a light-emitting element including, between a pair ofelectrodes, an EL layer having a light-emitting layer. Specifically, anEL layer 103 is provided between a first electrode 101 and a secondelectrode 102.

FIG. 1B illustrates a light-emitting element that has a stacked-layerstructure (tandem structure) in which a plurality of EL layers (two ELlayers 103 a and 103 b in FIG. 1B) are provided between a pair ofelectrodes and a charge-generation layer 104 is provided between the ELlayers. With the use of such a tandem light-emitting element, alight-emitting device which can be driven at low voltage with low powerconsumption can be obtained.

The charge-generation layer 104 has a function of injecting electronsinto one of the EL layers (103 a or 103 b) and injecting holes into theother of the EL layers (103 b or 103 a) when voltage is applied betweenthe first electrode 101 and the second electrode 102. Thus, when voltageis applied in FIG. 1B such that the potential of the first electrode 101is higher than that of the second electrode 102, the charge-generationlayer 104 injects electrons into the EL layer 103 a and injects holesinto the EL layer 103 b.

Note that in terms of light extraction efficiency, the charge-generationlayer 104 preferably has a property of transmitting visible light(specifically, the charge-generation layer 104 has a visible lighttransmittance of 40% or more). The charge-generation layer 104 functionseven when it has lower conductivity than the first electrode 101 or thesecond electrode 102.

FIG. 1C illustrates a stacked-layer structure of the EL layer 103 in thelight-emitting element of one embodiment of the present invention. Inthis case, the first electrode 101 is regarded as functioning as ananode. The EL layer 103 has a structure in which a hole-injection layer111, a hole-transport layer 112, a light-emitting layer 113, anelectron-transport layer 114, and an electron-injection layer 115 arestacked in this order over the first electrode 101. Even in the casewhere a plurality of EL layers are provided as in the tandem structureillustrated in FIG. 1 i , the layers in each EL layer are sequentiallystacked from the anode side as described above. When the first electrode101 is a cathode and the second electrode 102 is an anode, the stackingorder is reversed.

The light-emitting layer 113 included in the EL layers (103, 103 a, and103 b) contains an appropriate combination of a light-emitting substanceand a plurality of substances, so that fluorescence or phosphorescenceof a desired emission color can be obtained. The light-emitting layer113 may have a stacked-layer structure having different emission colors.In that case, the light-emitting substance and other substances aredifferent between the stacked light-emitting layers. Alternatively, theplurality of EL layers (103 a and 103 b) in FIG. 1B may exhibit theirrespective emission colors. Also in that case, the light-emittingsubstance and other substances are different between the light-emittinglayers.

In the light-emitting element of one embodiment of the presentinvention, for example, a micro optical resonator (microcavity)structure in which the first electrode 101 is a reflective electrode andthe second electrode 102 is a transflective electrode can be employed inFIG. 1C, whereby light emission from the light-emitting layer 113 in theEL layer 103 can be resonated between the electrodes and light emissionobtained through the second electrode 102 can be intensified.

Note that when the first electrode 101 of the light-emitting element isa reflective electrode having a structure in which a reflectiveconductive material and a light-transmitting conductive material(transparent conductive film) are stacked, optical adjustment can beperformed by controlling the thickness of the transparent conductivefilm. Specifically, when the wavelength of light obtained from thelight-emitting layer 113 is λ, the distance between the first electrode101 and the second electrode 102 is preferably adjusted to around mλ/2(m is a natural number).

To amplify desired light (wavelength: k) obtained from thelight-emitting layer 113, the optical path length from the firstelectrode 101 to a region where the desired light is obtained in thelight-emitting layer 113 (light-emitting region) and the optical pathlength from the second electrode 102 to the region where the desiredlight is obtained in the light-emitting layer 113 (light-emittingregion) are preferably adjusted to around (2m′+1)λ/4 (m′ is a naturalnumber). Here, the light-emitting region means a region where holes andelectrons are recombined in the light-emitting layer 113.

By such optical adjustment, the spectrum of specific monochromatic lightobtained from the light-emitting layer 113 can be narrowed and lightemission with high color purity can be obtained.

In that case, the optical path length between the first electrode 101and the second electrode 102 is, to be exact, the total thickness from areflective region in the first electrode 101 to a reflective region inthe second electrode 102. However, it is difficult to preciselydetermine the reflective regions in the first electrode 101 and thesecond electrode 102; thus, it is assumed that the above effect can besufficiently obtained wherever the reflective regions may be set in thefirst electrode 101 and the second electrode 102. Furthermore, theoptical path length between the first electrode 101 and thelight-emitting layer emitting the desired light is, to be exact, theoptical path length between the reflective region in the first electrode101 and the light-emitting region in the light-emitting layer emittingthe desired light. However, it is difficult to precisely determine thereflective region in the first electrode 101 and the light-emittingregion in the light-emitting layer emitting the desired light; thus, itis assumed that the above effect can be sufficiently obtained whereverthe reflective region and the light-emitting region may be set in thefirst electrode 101 and the light-emitting layer emitting the desiredlight.

The light-emitting element in FIG. 1C has a microcavity structure, sothat light (monochromatic light) with different wavelengths can beextracted even if the same EL layer is used. Thus, separate coloring forobtaining a plurality of emission colors (e.g., R, G, and B) is notnecessary. Therefore, high resolution can be easily achieved. Note thata combination with coloring layers (color filters) is also possible.Furthermore, emission intensity of light with a specific wavelength inthe front direction can be increased, whereby power consumption can bereduced.

A light-emitting element illustrated in FIG. 1E is an example of thelight-emitting element with the tandem structure illustrated in FIG. 1B,and includes three EL layers (103 a, 103 b, and 103 c) stacked withcharge-generation layers (104 a and 104 b) positioned therebetween, asillustrated in the figure. The three EL layers (103 a, 103 b, and 103 c)include respective light-emitting layers (113 a, 113 b, and 113 c) andthe emission colors of the light-emitting layers can be selected freely.For example, the light-emitting layer 113 a can be blue, thelight-emitting layer 113 b can be red, green, or yellow, and thelight-emitting layer 113 c can be blue. For another example, thelight-emitting layer 113 a can be red, the light-emitting layer 113 bcan be blue, green, or yellow, and the light-emitting layer 113 c can bered.

In the light-emitting element of one embodiment of the presentinvention, at least one of the first electrode 101 and the secondelectrode 102 is a light-transmitting electrode (e.g., a transparentelectrode or a transflective electrode). In the case where thelight-transmitting electrode is a transparent electrode, the transparentelectrode has a visible light transmittance of higher than or equal to40%. In the case where the light-transmitting electrode is atransflective electrode, the transflective electrode has a visible lightreflectance of higher than or equal to 20% and lower than or equal to80%, and preferably higher than or equal to 40% and lower than or equalto 70%. These electrodes preferably have a resistivity of 1×10⁻² Ωcm orless.

Furthermore, when one of the first electrode 101 and the secondelectrode 102 is a reflective electrode in the light-emitting element ofone embodiment of the present invention, the visible light reflectanceof the reflective electrode is higher than or equal to 40% and lowerthan or equal to 100%, and preferably higher than or equal to 70% andlower than or equal to 100%. This electrode preferably has a resistivityof 1×10⁻² Ωcm or less.

<<Specific Structure and Fabrication Method of Light-Emitting Element>>

Specific structures and specific fabrication methods of light-emittingelements of embodiments of the present invention will be described withreference to FIGS. 1A to 1E. Here, a light-emitting element having thetandem structure in FIG. 1B and a microcavity structure will bedescribed with reference to FIG. 1D. In the light-emitting element inFIG. 1D, the first electrode 101 is formed as a reflective electrode andthe second electrode 102 is formed as a transflective electrode. Thus, asingle-layer structure or a stacked-layer structure can be formed usingone or more kinds of desired electrode materials. Note that the secondelectrode 102 is formed after formation of the EL layer 103 b, with theuse of a material selected as described above. For fabrication of theseelectrodes, a sputtering method or a vacuum evaporation method can beused.

<First Electrode and Second Electrode>

As materials used for the first electrode 101 and the second electrode102, any of the following materials can be used in an appropriatecombination as long as the functions of the electrodes described abovecan be fulfilled. For example, a metal, an alloy, an electricallyconductive compound, a mixture of these, and the like can beappropriately used. Specifically, an In—Sn oxide (also referred to asITO), an In—Si—Sn oxide (also referred to as ITSO), an In—Zn oxide, anIn—W—Zn oxide, or the like can be used. In addition, it is possible touse a metal such as aluminum (Al), titanium (Ti), chromium (Cr),manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu),gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo),tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt),silver (Ag), yttrium (Y), or neodymium (Nd) or an alloy containing anappropriate combination of any of these metals. It is also possible touse a Group 1 element or a Group 2 element in the periodic table, whichis not described above (e.g., lithium (Li), cesium (Cs), calcium (Ca),or strontium (Sr)), a rare earth metal such as europium (Eu) orytterbium (Yb), an alloy containing an appropriate combination of any ofthese elements, graphene, or the like.

In the light-emitting element in FIG. 1D, when the first electrode 101is an anode, a hole-injection layer 111 a and a hole-transport layer 112a of the EL layer 103 a are sequentially stacked over the firstelectrode 101 by a vacuum evaporation method. After the EL layer 103 aand the charge-generation layer 104 are formed, a hole-injection layer111 b and a hole-transport layer 112 b of the EL layer 103 b aresequentially stacked over the charge-generation layer 104 in a similarmanner.

<Hole-Injection Layer and Hole-Transport Layer>

The hole-injection layers (111, 111 a, and 111 b) inject holes from thefirst electrode 101 that is an anode and the charge-generation layer(104) to the EL layers (103, 103 a, and 103 b) and each contain amaterial with a high hole-injection property.

As examples of the material with a high hole-injection property,transition metal oxides such as molybdenum oxide, vanadium oxide,ruthenium oxide, tungsten oxide, and manganese oxide can be given.Alternatively, it is possible to use any of the following materials:phthalocyanine-based compounds such as phthalocyanine (abbreviation:H₂Pc) and copper phthalocyanine (abbreviation: CuPc); aromatic aminecompounds such as4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation:DPAB) andN,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(abbreviation: DNTPD); high molecular compounds such aspoly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid)(abbreviation: PEDOT/PSS); and the like.

Alternatively, as the material with a high hole-injection property, acomposite material containing a hole-transport material and an acceptormaterial (an electron-accepting material) can also be used. In thatcase, the acceptor material extracts electrons from the hole-transportmaterial, so that holes are generated in the hole-injection layers (111,111 a, and 111 b) and the holes are injected into the light-emittinglayers (113, 113 a, and 113 b) through the hole-transport layers (112,112 a, and 112 b). Note that each of the hole-injection layers (111, 111a, and 111 b) may be formed to have a single-layer structure using acomposite material containing a hole-transport material and an acceptormaterial (electron-accepting material), or a stacked-layer structure inwhich a layer including a hole-transport material and a layer includingan acceptor material (electron-accepting material) are stacked.

The hole-transport layers (112, 112 a, and 112 b) transport the holes,which are injected from the first electrode 101 and thecharge-generation layer (104) by the hole-injection layers (111, 111 a,and 111 b), to the light-emitting layers (113, 113 a, and 113 b). Notethat the hole-transport layers (112, 112 a, and 112 b) each contain ahole-transport material. It is particularly preferable that the HOMOlevel of the hole-transport material included in the hole-transportlayers (112, 112 a, and 112 b) be the same as or close to that of thehole-injection layers (111, 111 a, and 111 b).

Examples of the acceptor material used for the hole-injection layers(111, 111 a, and 111 b) include an oxide of a metal belonging to any ofGroups 4 to 8 of the periodic table. Specifically, molybdenum oxide,vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungstenoxide, manganese oxide, and rhenium oxide can be given. Among these,molybdenum oxide is especially preferable since it is stable in the air,has a low hygroscopic property, and is easy to handle. Alternatively,organic acceptors such as a quinodimethane derivative, a chloranilderivative, and a hexaazatriphenylene derivative can be used.Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane(abbreviation: F₄-TCNQ), chloranil,2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation:HAT-CN), and the like can be used.

The hole-transport materials used for the hole-injection layers (111,111 a, and 111 b) and the hole-transport layers (112, 112 a, and 112 b)are preferably substances with a hole mobility of greater than or equalto 10⁻⁶ cm²/Vs. Note that other substances may be used as long as thesubstances have a hole-transport property higher than anelectron-transport property.

Preferred hole-transport materials are π-electron rich heteroaromaticcompounds (e.g., carbazole derivatives and indole derivatives) andaromatic amine compounds, examples of which include compounds having anaromatic amine skeleton, such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB orα-NPD),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP), 4-phenyl-3′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: mBPAFLP),4-phenyl-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation:PCBA1BP), 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole(abbreviation: PCPPn),N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine(abbreviation: PCBiF),N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine(abbreviation: PCBBiF),4,4′-diphenyl-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBBi1BP),4-(1-naphthyl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBANB),4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBNBB),9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine(abbreviation: PCBAF),N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine(abbreviation: PCBASF), 4,4′,4″-tris(carbazol-9-yl)triphenylamine(abbreviation: TCTA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine(abbreviation: TDATA), and4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA); compounds having a carbazole skeleton, such as1,3-bis(N-carbazolyl)benzene (abbreviation: mCP),4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP),3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP),3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2),3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene(abbreviation: TCPB), and9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA);compounds having a thiophene skeleton, such as4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation:DBT3P-II),2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene(abbreviation: DBTFLP-III), and4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene(abbreviation: DBTFLP-IV); and compounds having a furan skeleton, suchas 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation:DBF3P-II) and4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran(abbreviation: mmDBFFLBi-II).

A high molecular compound such as poly(N-vinylcarbazole) (abbreviation:PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA), orpoly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation:Poly-TPD) can also be used.

Note that the hole-transport material is not limited to the aboveexamples and may be one of or a combination of various known materialswhen used for the hole-injection layers (111, 111 a, and 111 b) and thehole-transport layers (112, 112 a, and 112 b). Note that thehole-transport layers (112, 112 a, and 112 b) may each be formed of aplurality of layers. That is, for example, the hole-transport layers mayeach have a stacked-layer structure of a first hole-transport layer anda second hole-transport layer.

In the light-emitting element in FIG. 1D, the light-emitting layer 113 ais formed over the hole-transport layer 112 a of the EL layer 103 a by avacuum evaporation method. After the EL layer 103 a and thecharge-generation layer 104 are formed, the light-emitting layer 113 bis formed over the hole-transport layer 112 b of the EL layer 103 b by avacuum evaporation method.

<Light-Emitting Layer>

The light-emitting layers (113, 113 a, 113 b, and 113 c) each contain alight-emitting substance. Note that as the light-emitting substance, asubstance whose emission color is blue, violet, bluish violet, green,yellowish green, yellow, orange, red, or the like is appropriately used.When the plurality of light-emitting layers (113 a, 113 b, and 113 c)are formed using different light-emitting substances, different emissioncolors can be exhibited (for example, complementary emission colors arecombined to achieve white light emission). Furthermore, a stacked-layerstructure in which one light-emitting layer contains two or more kindsof light-emitting substances may be employed.

The light-emitting layers (113, 113 a, 113 b, and 113 c) may eachcontain one or more kinds of organic compounds (a host material and anassist material) in addition to a light-emitting substance (guestmaterial). As the one or more kinds of organic compounds, one or both ofthe hole-transport material and the electron-transport materialdescribed in this embodiment can be used.

As the light-emitting substance that can be used for the light-emittinglayers (113, 113 a, 113 b, and 113 c), a light-emitting substance thatconverts singlet excitation energy into light emission in the visiblelight range or a light-emitting substance that converts tripletexcitation energy into light emission in the visible light range can beused.

Examples of other light-emitting substances are given below.

As an example of the light-emitting substance that converts singletexcitation energy into light emission, a substance that emitsfluorescence (fluorescent material) can be given. Examples of thesubstance that emits fluorescence include a pyrene derivative, ananthracene derivative, a triphenylene derivative, a fluorene derivative,a carbazole derivative, a dibenzothiophene derivative, a dibenzofuranderivative, a dibenzoquinoxaline derivative, a quinoxaline derivative, apyridine derivative, a pyrimidine derivative, a phenanthrene derivative,and a naphthalene derivative. A pyrene derivative is particularlypreferable because it has a high emission quantum yield. Specificexamples of the pyrene derivative includeN,N′-bis(3-methylphenyl)-N,N′-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine(abbreviation: 1,6mMemFLPAPrn),N,N′-diphenyl-N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine(abbreviation: 1,6FLPAPrn),N,N′-bis(dibenzofuran-2-yl)-N,N′-diphenylpyrene-1,6-diamine(abbreviation: 1,6FrAPrn),N,N′-bis(dibenzothiophen-2-yl)-N,N′-diphenylpyrene-1,6-diamine(abbreviation: 1,6ThAPrn),N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine](abbreviation:1,6BnfAPrn),N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 1,6BnfAPrn-02), andN,N′-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 1,6BnfAPrn-03).

In addition, it is possible to use5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2′-bipyridine (abbreviation:PAP2BPy), 5,6-bis[4′-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2′-bipyridine(abbreviation: PAPP2BPy),N,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine(abbreviation: YGA2S),4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine(abbreviation: YGAPA),4-(9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine(abbreviation: 2YGAPPA),N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: PCAPA),4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPA),4-[4-(10-phenyl-9-anthryl)phenyl]-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra(tert-butyl)perylene(abbreviation: TBP),N,N″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N′,N′-triphenyl-1,4-phenylenediamine](abbreviation: DPABPA),N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: 2PCAPPA),N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPPA), or the like.

As examples of a light-emitting substance that converts tripletexcitation energy into light emission, a substance that emitsphosphorescence (phosphorescent material) and a thermally activateddelayed fluorescence (TADF) material that exhibits thermally activateddelayed fluorescence can be given.

Examples of a phosphorescent material include an organometallic complex,a metal complex (platinum complex), and a rare earth metal complex.These substances exhibit the respective emission colors (emission peaks)and thus, any of them is appropriately selected according to need.

As examples of a phosphorescent material which emits blue or green lightand whose emission spectrum has a peak wavelength at greater than orequal to 450 nm and less than or equal to 570 nm, the followingsubstances can be given.

For example, organometallic complexes having a 4H-triazole skeleton,such astris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN²]phenyl-κC}iridium(III)(abbreviation: [Ir(mpptz-dmp)₃]),tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III)(abbreviation: [Ir(Mptz)₃]),tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(iPrptz-3b)₃]), andtris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(iPr5btz)₃]); organometallic complexes having a1H-triazole skeleton, such astris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(Mptz1-mp)₃]) andtris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III)(abbreviation: [Ir(Prptz1-Me)₃]); organometallic complexes having animidazole skeleton, such asfac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III)(abbreviation: [Ir(iPrpmi)₃]) andtris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III)(abbreviation: [Ir(dmpimpt-Me)₃]); organometallic complexes in which aphenylpyridine derivative having an electron-withdrawing group is aligand, such as bis[2-(4′,6′-difluorophenyl)pyridinato-N,C²]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: FIr6),bis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III) picolinate(abbreviation: FIrpic),bis{2-[3′,5′-bis(trifluoromethyl)phenyl]pyridinato-N,C^(2′)}iridium(III)picolinate (abbreviation: [Ir(CF₃ppy)₂(pic)]), andbis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)acetylacetonate (abbreviation: FIr(acac)); and the like can be given.

As examples of a phosphorescent material which emits green or yellowlight and whose emission spectrum has a peak wavelength at greater thanor equal to 495 nm and less than or equal to 590 nm, the followingsubstances can be given.

For example, organometallic iridium complexes having a pyrimidineskeleton, such as tris(4-methyl-6-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(mppm)₃]),tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation:[Ir(tBuppm)₃]),(acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(mppm)₂(acac)]),(acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(tBuppm)₂(acac)]),(acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III)(abbreviation: [Ir(nbppm)₂(acac)]),(acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III)(abbreviation: [Ir(mpmppm)₂(acac)]),(acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN³]phenyl-κC}iridium(III)(abbreviation: [Ir(dmppm-dmp)₂(acac)]), and(acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)(abbreviation: [Ir(dppm)₂(acac)]); organometallic iridium complexeshaving a pyrazine skeleton, such as(acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III)(abbreviation: [Ir(mppr-Me)₂(acac)]) and(acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III)(abbreviation: [Ir(mppr-iPr)₂(acac)]); organometallic iridium complexeshaving a pyridine skeleton, such astris(2-phenylpyridinato-N,C^(2′))iridium(III) (abbreviation:[Ir(ppy)₃]), bis(2-phenylpyridinato-N,C^(2′))iridium(III)acetylacetonate (abbreviation: [Ir(ppy)₂(acac)]),bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation:[Ir(bzq)₂(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation:[Ir(bzq)₃]), tris(2-phenylquinolinato-N,C^(2′))iridium(III)(abbreviation: [Ir(pq)₃]), andbis(2-phenylquinolinato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: [Ir(pq)₂(acac)]); organometallic complexes such asbis(2,4-diphenyl-1,3-oxazolato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: [Ir(dpo)₂(acac)]),bis{2-[4′-(perfluorophenyl)phenyl]pyridinato-N,C^(2′)}iridium(III)acetylacetonate (abbreviation: [Ir(p-PF-ph)₂(acac)]), andbis(2-phenylbenzothiazolato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: [Ir(bt)₂(acac)]); and rare earth metal complexes such astris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation:[Tb(acac)₃(Phen)]) can be given.

As examples of a phosphorescent material which emits yellow or red lightand whose emission spectrum has a peak wavelength at greater than orequal to 570 nm and less than or equal to 750 nm, the followingsubstances can be given.

For example, organometallic complexes having a pyrimidine skeleton, suchas(diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III)(abbreviation: [Ir(5mdppm)₂(dibm)]),bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III)(abbreviation: [Ir(5mdppm)₂(dpm)]), andbis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III)(abbreviation: [Ir(d1npm)₂(dpm)]); organometallic complexes having apyrazine skeleton, such as(acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III)(abbreviation: [Ir(tppr)₂(acac)]),bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III)(abbreviation: [Ir(tppr)₂(dpm)]),bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-P)₂(dibm)]),bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-dmCP)₂(dpm)]),(acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C^(2′)]iridium(III)(abbreviation: [Ir(mpq)₂(acac)]),(acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C^(2′))iridium(III)(abbreviation: [Ir(dpq)₂(acac)]), and(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(abbreviation: [Ir(Fdpq)₂(acac)]); organometallic complexes having apyridine skeleton, such astris(1-phenylisoquinolinato-N,C^(2′))iridium(III) (abbreviation:[Ir(piq)₃]) and bis(1-phenylisoquinolinato-N,C^(2′))iridium(III)acetylacetonate (abbreviation: [Ir(piq)₂(acac)]); platinum complexessuch as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II)(abbreviation: [PtOEP]); and rare earth metal complexes such astris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III)(abbreviation: [Eu(DBM)₃(Phen)]) andtris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III)(abbreviation: [Eu(TTA)₃(Phen)]) can be given.

As the organic compounds (the host material and the assist material)used in the light-emitting layers (113, 113 a, 113 b, and 113 c), one ormore kinds of substances having a larger energy gap than thelight-emitting substance (the guest material) are used.

When the light-emitting substance is a fluorescent material, it ispreferable to use, as the host material, an organic compound that has ahigh energy level in a singlet excited state and has a low energy levelin a triplet excited state. For example, an anthracene derivative or atetracene derivative is preferably used. Specific examples thereofinclude 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole(abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole(abbreviation: CzPA),7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA),6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan(abbreviation: 2mBnfPPA),9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)-biphenyl-4′-yl}anthracene(abbreviation: FLPPA), 5,12-diphenyltetracene, and5,12-bis(biphenyl-2-yl)tetracene.

In the case where the light-emitting substance is a phosphorescentmaterial, an organic compound having triplet excitation energy (energydifference between a ground state and a triplet excited state) which ishigher than that of the light-emitting substance is preferably selectedas the host material. In that case, it is possible to use a zinc- oraluminum-based metal complex, an oxadiazole derivative, a triazolederivative, a benzimidazole derivative, a quinoxaline derivative, adibenzoquinoxaline derivative, a dibenzothiophene derivative, adibenzofuran derivative, a pyrimidine derivative, a triazine derivative,a pyridine derivative, a bipyridine derivative, a phenanthrolinederivative, an aromatic amine, a carbazole derivative, and the like.

More specifically, any of the following hole-transport materials andelectron-transport materials can be used as the host material, forexample.

Examples of the host material having a high hole-transport propertyinclude aromatic amine compounds such asN,N′-di(p-tolyl)-N,N′-diphenyl-p-phenylenediamine (abbreviation:DTDPPA), 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl(abbreviation: DPAB),N,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(abbreviation: DNTPD), and1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene(abbreviation: DPA3B).

Carbazole derivatives such as3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzDPA1),3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzDPA2),3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole(abbreviation: PCzTPN2),3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2), and3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1) are also given. Other examples of the carbazolederivative include 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.

Examples of the host material having a high hole-transport propertyinclude aromatic amine compounds such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB orα-NPD),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD), 4,4′,4″-tris(carbazol-9-yl)triphenylamine(abbreviation: TCTA),4,4′,4″-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation:1′-TNATA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation:TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: m-MTDATA),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP), 4-phenyl-3′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: mBPAFLP),N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N′-phenyl-N′-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine(abbreviation: DFLADFL),N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine(abbreviation: DPNF),2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9′-bifluorene(abbreviation: DPASF),4-phenyl-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation:PCBA1BP), 4,4′-diphenyl-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBBi1BP),4-(1-naphthyl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBANB),4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBNBB),4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation:PCA1BP),N,N′-bis(9-phenylcarbazol-3-yl)-N,N′-diphenylbenzene-1,3-diamine(abbreviation: PCA2B),N,N′,N″-triphenyl-N,N′,N″-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine(abbreviation: PCA3B),N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine(abbreviation: PCBiF),N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine(abbreviation: PCBBiF),9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine(abbreviation: PCBAF),N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine(abbreviation: PCBASF),2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9′-bifluorene(abbreviation: PCASF),2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9′-bifluorene(abbreviation: DPA2SF),N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation:YGA1BP), andN,N′-bis[4-(carbazol-9-yl)phenyl]-N,N′-diphenyl-9,9-dimethylfluorene-2,7-diamine(abbreviation: YGA2F). Other examples are carbazole compounds, thiophenecompounds, furan compounds, fluorene compounds, triphenylene compounds,phenanthrene compounds, and the like such as3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN),3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation:PCPPn), 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP),1,3-bis(N-carbazolyl)benzene (abbreviation: mCP),3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP),4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran(abbreviation: mmDBFFLBi-II),4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II),1,3,5-tri(dibenzothiophen-4-yl)-benzene (abbreviation: DBT3P-II),2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene(abbreviation: DBTFLP-III),4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene(abbreviation: DBTFLP-IV), and4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation:mDBTPTp-II).

Examples of the host material having a high electron-transport propertyinclude a metal complex having a quinoline skeleton or a benzoquinolineskeleton, such as tris(8-quinolinolato)aluminum(III) (abbreviation:Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq₃),bis(10-hydroxybenzo[h]-quinolinato)beryllium(II) (abbreviation: BeBq2),bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III)(abbreviation: BAlq), or bis(8-quinolinolato)zinc(II) (abbreviation.:Znq). Alternatively, a metal complex having an oxazole-based orthiazole-based ligand, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II)(abbreviation: ZnPBO) or bis[2-(2-benzothiazolyl)phenolato]zinc(II)(abbreviation: ZnBTZ) can be used. Other than such metal complexes, anyof the following can be used: oxadiazole derivatives such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviation: OXD-7), and9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation:COl1); a triazole derivative such as3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole(abbreviation: TAZ); a compound having an imidazole skeleton (inparticular, a benzimidazole derivative) such as2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole)(abbreviation: TPBI) or2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole(abbreviation: mDBTBIm-II); a compound having an oxazole skeleton (inparticular, a benzoxazole derivative) such as4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs); aphenanthroline derivative such as bathophenanthroline (abbreviation:Bphen), bathocuproine (abbreviation: BCP), and2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation:NBphen); heterocyclic compounds having a diazine skeleton such as2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:2mDBTPDBq-II),2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II),2-[3′-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mCzBPDBq),2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline(abbreviation: 2CzPDBq-III),7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline(abbreviation: 6mDBTPDBq-II),4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation:4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine(abbreviation: 4,6mDBTP2Pm-II), and4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation:4,6mCzP2Pm); heterocyclic compounds having a triazine skeleton such as2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine(abbreviation: PCCzPTzn); heterocyclic compounds having a pyridineskeleton such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine(abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene(abbreviation: TmPyPB). Further alternatively, a high molecular compoundsuch as poly(2,5-pyridinediyl) (abbreviation: PPy),poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation: PF-Py) orpoly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation: PF-BPy) can be used.

Examples of the host material include condensed polycyclic aromaticcompounds such as anthracene derivatives, phenanthrene derivatives,pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysenederivatives. Specific examples of the condensed polycyclic aromaticcompound include 9,10-diphenylanthracene (abbreviation: DPAnth),N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine(abbreviation: DPhPA), YGAPA, PCAPA,N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine(abbreviation: PCAPBA), 2PCAPA, 6,12-dimethoxy-5,11-diphenylchrysene,DBC1, 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation:CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anthracene(abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA),2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA),9,9′-bianthryl (abbreviation: BANT),9,9′-(stilbene-3,3′-diyl)diphenanthrene (abbreviation: DPNS),9,9′-(stilbene-4,4′-diyl)diphenanthrene (abbreviation: DPNS2), and1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3).

In the case where a plurality of organic compounds are used for thelight-emitting layers (113, 113 a, 113 b, and 113 c), it is possible touse two compounds that form an exciplex (a first compound and a secondcompound) combined with an organometallic complex. In that case,although any of various organic compounds can be combined appropriatelyto be used, to form an exciplex efficiently, it is particularlypreferable to combine a compound that easily accepts holes (ahole-transport material) and a compound that easily accepts electrons(an electron-transport material). As the hole-transport material and theelectron-transport material, specifically, any of the materialsdescribed in this embodiment can be used. With the above structure, highefficiency, low voltage, and a long lifetime can be achieved at the sametime.

The TADF material is a material that can up-convert a triplet excitedstate into a singlet excited state (i.e., reverse intersystem crossingis possible) using a little thermal energy and efficiently exhibitslight emission (fluorescence) from the singlet excited state. The TADFis efficiently obtained under the condition where the difference inenergy between the triplet excited level and the singlet excited levelis greater than or equal to 0 eV and less than or equal to 0.2 eV,preferably greater than or equal to 0 eV and less than or equal to 0.1eV. Note that “delayed fluorescence” exhibited by the TADF materialrefers to light emission having the same spectrum as normal fluorescenceand an extremely long lifetime. The lifetime is 10⁻⁶ seconds or longer,preferably 10⁻³ seconds or longer.

Examples of the TADF material include fullerene, a derivative thereof,an acridine derivative such as proflavine, and eosin. Other examplesinclude a metal-containing porphyrin, such as a porphyrin containingmagnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium(In), or palladium (Pd). Examples of the metal-containing porphyrininclude a protoporphyrin-tin fluoride complex (abbreviation: SnF₂(ProtoIX)), a mesoporphyrin-tin fluoride complex (abbreviation: SnF₂(MesoIX)), a hematoporphyrin-tin fluoride complex (abbreviation: SnF₂(HematoIX)), a coproporphyrin tetramethyl ester-tin fluoride complex(abbreviation: SnF₂(Copro III-4Me)), an octaethylporphyrin-tin fluoridecomplex (abbreviation: SnF₂(OEP)), an etioporphyrin-tin fluoride complex(abbreviation: SnF₂(Etio I)), and an octaethylporphyrin-platinumchloride complex (abbreviation: PtCl₂OEP).

Alternatively, a heterocyclic compound having a π-electron richheteroaromatic ring and a π-electron deficient heteroaromatic ring, suchas2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine(abbreviation: PIC-TRZ),2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine(abbreviation: PCCzPTzn),2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine(abbreviation: PXZ-TRZ),3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole(abbreviation: PPZ-3TPT),3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation:ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone(abbreviation: DMAC-DPS), or10-phenyl-10H,10′H-spiro[acridin-9,9′-anthracen]-10′-one (abbreviation:ACRSA) can be used. Note that a substance in which the π-electron richheteroaromatic ring is directly bonded to the π-electron deficientheteroaromatic ring is particularly preferable because both the donorproperty of the π-electron rich heteroaromatic ring and the acceptorproperty of the π-electron deficient heteroaromatic ring are increasedand the energy difference between the singlet excited state and thetriplet excited state becomes small.

Note that when a TADF material is used, the TADF material can becombined with another organic compound.

In the light-emitting element in FIG. 1D, the electron-transport layer114 a is formed over the light-emitting layer 113 a of the EL layer 103a by a vacuum evaporation method. After the EL layer 103 a and thecharge-generation layer 104 are formed, the electron-transport layer 114b is formed over the light-emitting layer 113 b of the EL layer 103 b bya vacuum evaporation method.

<Electron-Transport Layer>

The electron-transport layers (114, 114 a, and 114 b) transport theelectrons, which are injected from the second electrode 102 and thecharge-generation layer (104) by the electron-injection layers (115, 115a, and 115 b), to the light-emitting layers (113, 113 a, and 113 b).Note that the electron-transport layers (114, 114 a, and 114 b) eachcontain an electron-transport material. It is preferable that theelectron-transport materials included in the electron-transport layers(114, 114 a, and 114 b) be substances with an electron mobility ofhigher than or equal to 1×10⁻⁶ cm²/Vs. Note that other substances mayalso be used as long as the substances have an electron-transportproperty higher than a hole-transport property.

Examples of the electron-transport material include metal complexeshaving a quinoline ligand, a benzoquinoline ligand, an oxazole ligand,and a thiazole ligand; an oxadiazole derivative; a triazole derivative;a phenanthroline derivative; a pyridine derivative; and a bipyridinederivative. In addition, a π-electron deficient heteroaromatic compoundsuch as a nitrogen-containing heteroaromatic compound can also be used.

Specifically, it is possible to use metal complexes such as Alq₃,tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq₃),bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq₂), BAlq,bis[2-(2-hydroxyphenyl)benzoxazolato]zinc(II) (abbreviation: Zn(BOX)₂),and bis[2-(2-hydroxyphenyl)benzothiazolato]zinc (abbreviation:Zn(BTZ)₂), heteroaromatic compounds such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), OXD-7,3-(4′-tert-butylphenyl)-4-phenyl-5-(4″-biphenyl)-1,2,4-triazole(abbreviation: TAZ),3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole(abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen),bathocuproine (abbreviation: BCP), and4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), andquinoxaline derivatives and dibenzoquinoxaline derivatives such as2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:2mDBTPDBq-II),2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II),2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline(abbreviation: 2CzPDBq-III),7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:7mDBTPDBq-II), and6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:6mDBTPDBq-II).

Further alternatively, a high molecular compound such aspoly(2,5-pyridinediyl) (abbreviation: PPy),poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation: PF-Py) orpoly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation: PF-BPy) can be used.

Each of the electron-transport layers (114, 114 a, and 114 b) is notlimited to a single layer, but may be a stack of two or more layers eachcontaining any of the above substances.

In the light-emitting element in FIG. 1D, the electron-injection layer115 a is formed over the electron-transport layer 114 a of the EL layer103 a by a vacuum evaporation method. Subsequently, the EL layer 103 aand the charge-generation layer 104 are formed, the components up to theelectron-transport layer 114 b of the EL layer 103 b are formed, andthen the electron-injection layer 115 b is formed thereover by a vacuumevaporation method.

<Electron-Injection Layer>

The electron-injection layers (115, 115 a, and 115 b) each contain asubstance having a high electron-injection property. Theelectron-injection layers (115, 115 a, and 115 b) can each be formedusing an alkali metal, an alkaline earth metal, or a compound thereof,such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride(CaF₂), or lithium oxide (LiOx). A rare earth metal compound like erbiumfluoride (ErF₃) can also be used. Electride may also be used for theelectron-injection layers (115, 115 a, and 115 b). Examples of theelectride include a substance in which electrons are added at highconcentration to calcium oxide-aluminum oxide. Any of the substances forforming the electron-transport layers (114, 114 a, and 114 b), which aregiven above, can also be used.

A composite material in which an organic compound and an electron donor(donor) are mixed may also be used for the electron-injection layers(115, 115 a, and 115 b). Such a composite material is excellent in anelectron-injection property and an electron-transport property becauseelectrons are generated in the organic compound by the electron donor.The organic compound here is preferably a material excellent intransporting the generated electrons; specifically, for example, theelectron-transport materials for forming the electron-transport layers(114, 114 a, and 114 b) (e.g., a metal complex or a heteroaromaticcompound) can be used. As the electron donor, a substance showing anelectron-donating property with respect to the organic compound may beused. Preferable examples are an alkali metal, an alkaline earth metal,and a rare earth metal. Specifically, lithium, cesium, magnesium,calcium, erbium, ytterbium, and the like can be given. Furthermore, analkali metal oxide and an alkaline earth metal oxide are preferable, anda lithium oxide, a calcium oxide, a barium oxide, and the like can begiven. Alternatively, a Lewis base such as magnesium oxide can be used.Further alternatively, an organic compound such as tetrathiafulvalene(abbreviation: TTF) can be used.

In the case where light obtained from the light-emitting layer 113 b isamplified, for example, the optical path length between the secondelectrode 102 and the light-emitting layer 113 b is preferably less thanone fourth of the wavelength k of light emitted from the light-emittinglayer 113 b. In that case, the optical path length can be adjusted bychanging the thickness of the electron-transport layer 114 b or theelectron-injection layer 115 b.

<Charge-Generation Layer>

The charge-generation layer 104 has a function of injecting electronsinto the EL layer 103 a and injecting holes into the EL layer 103 b whena voltage is applied between the first electrode (anode) 101 and thesecond electrode (cathode) 102. The charge-generation layer 104 may haveeither a structure in which an electron acceptor (acceptor) is added toa hole-transport material or a structure in which an electron donor(donor) is added to an electron-transport material. Alternatively, bothof these structures may be stacked. Note that forming thecharge-generation layer 104 by using any of the above materials cansuppress an increase in drive voltage caused by the stack of the ELlayers.

In the case where the charge-generation layer 104 has a structure inwhich an electron acceptor is added to a hole-transport material, any ofthe materials described in this embodiment can be used as thehole-transport material. As the electron acceptor, it is possible to use7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation:F₄-TCNQ), chloranil, and the like. In addition, oxides of metals thatbelong to Group 4 to Group 8 of the periodic table can be given.Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromiumoxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide,or the like is used.

In the case where the charge-generation layer 104 has a structure inwhich an electron donor is added to an electron-transport material, anyof the materials described in this embodiment can be used as theelectron-transport material. As the electron donor, it is possible touse an alkali metal, an alkaline earth metal, a rare earth metal, metalsthat belong to Groups 2 and 13 of the periodic table, or an oxide orcarbonate thereof. Specifically, lithium (Li), cesium (Cs), magnesium(Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesiumcarbonate, or the like is preferably used. Alternatively, an organiccompound such as tetrathianaphthacene may be used as the electron donor.

Note that the EL layer 103 c in FIG. 1E has a structure similar to thoseof the above-described EL layers (103, 103 a, and 103 b). In addition,the charge-generation layers 104 a and 104 b each have a structuresimilar to that of the above-described charge-generation layer 104.

<Substrate>

The light-emitting element described in this embodiment can be formedover any of a variety of substrates. Note that the type of the substrateis not limited to a certain type. Examples of the substrate include asemiconductor substrate (e.g., a single crystal substrate or a siliconsubstrate), an SOI substrate, a glass substrate, a quartz substrate, aplastic substrate, a metal substrate, a stainless steel substrate, asubstrate including stainless steel foil, a tungsten substrate, asubstrate including tungsten foil, a flexible substrate, an attachmentfilm, paper including a fibrous material, and a base material film.

Examples of the glass substrate include a barium borosilicate glasssubstrate, an aluminoborosilicate glass substrate, and a soda lime glasssubstrate. Examples of the flexible substrate, the attachment film, andthe base material film include plastics typified by polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES); a synthetic resin such as acrylic; polypropylene;polyester; polyvinyl fluoride; polyvinyl chloride; polyamide; polyimide;aramid; epoxy; an inorganic vapor deposition film; and paper.

For fabrication of the light-emitting element in this embodiment, avacuum process such as an evaporation method or a solution process suchas a spin coating method or an ink-jet method can be used. When anevaporation method is used, a physical vapor deposition method (PVDmethod) such as a sputtering method, an ion plating method, an ion beamevaporation method, a molecular beam evaporation method, or a vacuumevaporation method, a chemical vapor deposition method (CVD method), orthe like can be used. Specifically, the functional layers (thehole-injection layers (111, 111 a, and 111 b), the hole-transport layers(112, 112 a, and 112 b), the light-emitting layers (113, 113 a, 113 b,and 113 c), the electron-transport layers (114, 114 a, and 114 b), theelectron-injection layers (115, 115 a, and 115 b)) included in the ELlayers and the charge-generation layers (104, 104 a, and 104 b) of thelight-emitting element can be formed by an evaporation method (e.g., avacuum evaporation method), a coating method (e.g., a dip coatingmethod, a die coating method, a bar coating method, a spin coatingmethod, or a spray coating method), a printing method (e.g., an ink-jetmethod, screen printing (stencil), offset printing (planography),flexography (relief printing), gravure printing, or micro-contactprinting), or the like.

Note that materials that can be used for the functional layers (thehole-injection layers (111, 111 a, and 111 b), the hole-transport layers(112, 112 a, and 112 b), the light-emitting layers (113, 113 a, 113 b,and 113 c), the electron-transport layers (114, 114 a, and 114 b), andthe electron-injection layers (115, 115 a, and 115 b)) that are includedin the EL layers (103, 103 a, and 103 b) and the charge-generationlayers (104, 104 a, and 104 b) in the light-emitting element describedin this embodiment are not limited to the above materials, and othermaterials can be used in combination as long as the functions of thelayers are fulfilled. For example, a high molecular compound (e.g., anoligomer, a dendrimer, or a polymer), a middle molecular compound (acompound between a low molecular compound and a high molecular compoundwith a molecular weight of 400 to 4000), an inorganic compound (e.g., aquantum dot material), or the like can be used. The quantum dot may be acolloidal quantum dot, an alloyed quantum dot, a core-shell quantum dot,a core quantum dot, or the like.

The structures described in this embodiment can be combined with any ofthe structures described in the other embodiments as appropriate.

Embodiment 3

In this embodiment, a light-emitting device of one embodiment of thepresent invention is described. Note that a light-emitting deviceillustrated in FIG. 2A is an active-matrix light-emitting device inwhich transistors (FETs) 202 are electrically connected tolight-emitting elements (203R, 203G, 203B, and 203W) over a firstsubstrate 201. The light-emitting elements (203R, 203G, 203B, and 203W)include a common EL layer 204 and each have a microcavity structure inwhich the optical path length between electrodes is adjusted dependingon the emission color of the light-emitting element. The light-emittingdevice is a top-emission light-emitting device in which light is emittedfrom the EL layer 204 through color filters (206R, 206G, and 206B)formed on a second substrate 205.

The light-emitting device illustrated in FIG. 2A is fabricated such thata first electrode 207 functions as a reflective electrode and a secondelectrode 208 functions as a transflective electrode. Note thatdescription in any of the other embodiments can be referred to asappropriate for electrode materials for the first electrode 207 and thesecond electrode 208.

In the case where the light-emitting element 203R functions as a redlight-emitting element, the light-emitting element 203G functions as agreen light-emitting element, the light-emitting element 203B functionsas a blue light-emitting element, and the light-emitting element 203Wfunctions as a white light-emitting element in FIG. 2A, for example, agap between the first electrode 207 and the second electrode 208 in thelight-emitting element 203R is adjusted to have an optical path length200R, a gap between the first electrode 207 and the second electrode 208in the light-emitting element 203G is adjusted to have an optical pathlength 200G, and a gap between the first electrode 207 and the secondelectrode 208 in the light-emitting element 203B is adjusted to have anoptical path length 200B as illustrated in FIG. 2B. Note that opticaladjustment can be performed in such a manner that a conductive layer210R is stacked over the first electrode 207 in the light-emittingelement 203R and a conductive layer 210G is stacked over the firstelectrode 207 in the light-emitting element 203G as illustrated in FIG.2B.

The second substrate 205 is provided with the color filters (206R, 206G,and 206B). Note that the color filters each transmit visible light in aspecific wavelength range and blocks visible light in a specificwavelength range. Thus, as illustrated in FIG. 2A, the color filter 206Rthat transmits only light in the red wavelength range is provided in aposition overlapping with the light-emitting element 203R, whereby redlight emission can be obtained from the light-emitting element 203R.Furthermore, the color filter 206G that transmits only light in thegreen wavelength range is provided in a position overlapping with thelight-emitting element 203G, whereby green light emission can beobtained from the light-emitting element 203G. Moreover, the colorfilter 206B that transmits only light in the blue wavelength range isprovided in a position overlapping with the light-emitting element 203B,whereby blue light emission can be obtained from the light-emittingelement 203B. Note that the light-emitting element 203W can emit whitelight without a color filter. Note that a black layer (black matrix) 209may be provided at an end portion of each color filter. The colorfilters (206R, 206G, and 206B) and the black layer 209 may be coveredwith an overcoat layer formed using a transparent material.

Although the light-emitting device in FIG. 2A has a structure in whichlight is extracted from the second substrate 205 side (top emissionstructure), a structure in which light is extracted from the firstsubstrate 201 side where the FETs 202 are formed (bottom emissionstructure) may be employed as illustrated in FIG. 2C. In the case of abottom-emission light-emitting device, the first electrode 207 is formedas a transflective electrode and the second electrode 208 is formed as areflective electrode. As the first substrate 201, a substrate having atleast a light-transmitting property is used. As illustrated in FIG. 2C,color filters (206R′, 206G′, and 206B′) are provided so as to be closerto the first substrate 201 than the light-emitting elements (203R, 203G,and 203B) are.

In FIG. 2A, the light-emitting elements are the red light-emittingelement, the green light-emitting element, the blue light-emittingelement, and the white light-emitting element; however, thelight-emitting elements of one embodiment of the present invention arenot limited to the above, and a yellow light-emitting element or anorange light-emitting element may be used. Note that description in anyof the other embodiments can be referred to as appropriate for materialsthat are used for the EL layers (a light-emitting layer, ahole-injection layer, a hole-transport layer, an electron-transportlayer, an electron-injection layer, a charge-generation layer, and thelike) to fabricate each of the light-emitting elements. In that case, acolor filter needs to be appropriately selected depending on theemission color of the light-emitting element.

With the above structure, a light-emitting device includinglight-emitting elements that exhibit a plurality of emission colors canbe fabricated.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 4

In this embodiment, a light-emitting device of one embodiment of thepresent invention is described.

The use of the element structure of the light-emitting element of oneembodiment of the present invention allows fabrication of anactive-matrix light-emitting device or a passive-matrix light-emittingdevice. Note that an active-matrix light-emitting device has a structureincluding a combination of a light-emitting element and a transistor(FET). Thus, each of a passive-matrix light-emitting device and anactive-matrix light-emitting device is one embodiment of the presentinvention. Note that any of the light-emitting elements described inother embodiments can be used in the light-emitting device described inthis embodiment.

In this embodiment, an active-matrix light-emitting device will bedescribed with reference to FIGS. 3A and 3B.

FIG. 3A is a top view illustrating the light-emitting device, and FIG.3B is a cross-sectional view taken along chain line A-A′ in FIG. 3A. Theactive-matrix light-emitting device includes a pixel portion 302, adriver circuit portion (source line driver circuit) 303, and drivercircuit portions (gate line driver circuits) (304 a and 304 b) that areprovided over a first substrate 301. The pixel portion 302 and thedriver circuit portions (303, 304 a, and 304 b) are sealed between thefirst substrate 301 and a second substrate 306 with a sealant 305.

A lead wiring 307 is provided over the first substrate 301. The leadwiring 307 is connected to an FPC 308 that is an external inputterminal. Note that the FPC 308 transmits a signal (e.g., a videosignal, a clock signal, a start signal, or a reset signal) or apotential from the outside to the driver circuit portions (303, 304 a,and 304 b). The FPC 308 may be provided with a printed wiring board(PWB). Note that the light-emitting device provided with an FPC or a PWBis included in the category of a light-emitting device.

FIG. 3B illustrates a cross-sectional structure of the light-emittingdevice.

The pixel portion 302 includes a plurality of pixels each of whichincludes an FET (switching FET) 311, an FET (current control FET) 312,and a first electrode 313 electrically connected to the FET 312. Notethat the number of FETs included in each pixel is not particularlylimited and can be set appropriately.

As FETs 309, 310, 311, and 312, for example, a staggered transistor oran inverted staggered transistor can be used without particularlimitation. A top-gate transistor, a bottom-gate transistor, or the likemay be used.

Note that there is no particular limitation on the crystallinity of asemiconductor that can be used for the FETs 309, 310, 311, and 312, andan amorphous semiconductor or a semiconductor having crystallinity (amicrocrystalline semiconductor, a polycrystalline semiconductor, asingle crystal semiconductor, or a semiconductor partly includingcrystal regions) may be used. A semiconductor having crystallinity ispreferably used, in which case deterioration of the transistorcharacteristics can be suppressed.

For the semiconductor, a Group 14 element, a compound semiconductor, anoxide semiconductor, an organic semiconductor, or the like can be used,for example. As a typical example, a semiconductor containing silicon, asemiconductor containing gallium arsenide, or an oxide semiconductorcontaining indium can be used.

The driver circuit portion 303 includes the FET 309 and the FET 310. TheFET 309 and the FET 310 may be formed with a circuit includingtransistors having the same conductivity type (either n-channeltransistors or p-channel transistors) or a CMOS circuit including ann-channel transistor and a p-channel transistor. Furthermore, a drivercircuit may be provided outside.

An end portion of the first electrode 313 is covered with an insulator314. The insulator 314 can be formed using an organic compound such as anegative photosensitive resin or a positive photosensitive resin(acrylic resin), or an inorganic compound such as silicon oxide, siliconoxynitride, or silicon nitride. The insulator 314 preferably has acurved surface with curvature at an upper end portion or a lower endportion thereof. In that case, favorable coverage with a film formedover the insulator 314 can be obtained.

An EL layer 315 and a second electrode 316 are stacked over the firstelectrode 313. The EL layer 315 includes a light-emitting layer, ahole-injection layer, a hole-transport layer, an electron-transportlayer, an electron-injection layer, a charge-generation layer, and thelike.

The structure and materials described in any of the other embodimentscan be used for the components of a light-emitting element 317 describedin this embodiment. Although not illustrated, the second electrode 316is electrically connected to the FPC 308 that is an external inputterminal.

Although the cross-sectional view in FIG. 3B illustrates only onelight-emitting element 317, a plurality of light-emitting elements arearranged in a matrix in the pixel portion 302. Light-emitting elementsthat emit light of three kinds of colors (R, G, and B) are selectivelyformed in the pixel portion 302, whereby a light-emitting device capableof displaying a full-color image can be obtained. In addition to thelight-emitting elements that emit light of three kinds of colors (R, G,and B), for example, light-emitting elements that emit light of white(W), yellow (Y), magenta (M), cyan (C), and the like may be formed. Forexample, the light-emitting elements that emit light of some of theabove colors are used in combination with the light-emitting elementsthat emit light of three kinds of colors (R, G, and B), whereby effectssuch as an improvement in color purity and a reduction in powerconsumption can be achieved. Alternatively, a light-emitting devicewhich is capable of displaying a full-color image may be fabricated by acombination with color filters. As color filters, red (R), green (G),blue (B), cyan (C), magenta (M), and yellow (Y) color filters and thelike can be used.

When the second substrate 306 and the first substrate 301 are bonded toeach other with the sealant 305, the FETs (309, 310, 311, and 312) andthe light-emitting element 317 over the first substrate 301 are providedin a space 318 surrounded by the first substrate 301, the secondsubstrate 306, and the sealant 305. Note that the space 318 may befilled with an inert gas (e.g., nitrogen or argon) or an organicsubstance (including the sealant 305).

An epoxy-based resin, glass frit, or the like can be used for thesealant 305. It is preferable to use a material that is permeable to aslittle moisture and oxygen as possible for the sealant 305. As thesecond substrate 306, a substrate that can be used as the firstsubstrate 301 can be similarly used. Thus, any of the various substratesdescribed in the other embodiments can be appropriately used. As thesubstrate, a glass substrate, a quartz substrate, or a plastic substratemade of fiber-reinforced plastic (FRP), polyvinyl fluoride (PVF),polyester, acrylic, or the like can be used. In the case where glassfrit is used for the sealant, the first substrate 301 and the secondsubstrate 306 are preferably glass substrates in terms of adhesion.

Accordingly, the active-matrix light-emitting device can be obtained.

In the case where the active-matrix light-emitting device is providedover a flexible substrate, the FETs and the light-emitting element maybe directly formed over the flexible substrate; alternatively, the FETsand the light-emitting element may be formed over a substrate providedwith a separation layer and then separated at the separation layer byapplication of heat, force, laser, or the like to be transferred to aflexible substrate. For the separation layer, a stack includinginorganic films such as a tungsten film and a silicon oxide film, or anorganic resin film of polyimide or the like can be used, for example.Examples of the flexible substrate include, in addition to a substrateover which a transistor can be formed, a paper substrate, a cellophanesubstrate, an aramid film substrate, a polyimide film substrate, a clothsubstrate (including a natural fiber (e.g., silk, cotton, or hemp), asynthetic fiber (e.g., nylon, polyurethane, or polyester), a regeneratedfiber (e.g., acetate, cupra, rayon, or regenerated polyester), or thelike), a leather substrate, and a rubber substrate. With the use of anyof these substrates, an increase in durability, an increase in heatresistance, a reduction in weight, and a reduction in thickness can beachieved.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 5

In this embodiment, examples of a variety of electronic devices and anautomobile manufactured using the light-emitting device of oneembodiment of the present invention or a display device including thelight-emitting element of one embodiment of the present invention aredescribed.

Electronic devices illustrated in FIGS. 4A to 4E can include a housing7000, a display portion 7001, a speaker 7003, an LED lamp 7004,operation keys 7005 (including a power switch or an operation switch), aconnection terminal 7006, a sensor 7007 (a sensor having a function ofmeasuring or sensing force, displacement, position, speed, acceleration,angular velocity, rotational frequency, distance, light, liquid,magnetism, temperature, chemical substance, sound, time, hardness,electric field, current, voltage, electric power, radiation, flow rate,humidity, gradient, oscillation, odor, or infrared ray), a microphone7008, and the like.

FIG. 4A illustrates a mobile computer that can include a switch 7009, aninfrared port 7010, and the like in addition to the above components.

FIG. 4B illustrates a portable image reproducing device (e.g., a DVDplayer) that is provided with a recording medium and can include asecond display portion 7002, a recording medium reading portion 7011,and the like in addition to the above components.

FIG. 4C illustrates a goggle-type display that can include the seconddisplay portion 7002, a support 7012, an earphone 7013, and the like inaddition to the above components.

FIG. 4D illustrates a digital camera that has a television receptionfunction and can include an antenna 7014, a shutter button 7015, animage receiving portion 7016, and the like in addition to the abovecomponents.

FIG. 4E illustrates a cellular phone (including a smartphone) and caninclude the display portion 7001, a microphone 7019, the speaker 7003, acamera 7020, an external connection portion 7021, an operation button7022, and the like in the housing 7000.

FIG. 4F illustrates a large-size television set (also referred to as TVor a television receiver) and can include the housing 7000, the displayportion 7001, the speaker 7003, and the like. In addition, here, thehousing 7000 is supported by a stand 7018.

The electronic devices illustrated in FIGS. 4A to 4F can have a varietyof functions, such as a function of displaying a variety of data (astill image, a moving image, a text image, and the like) on the displayportion, a touch panel function, a function of displaying a calendar,date, time, and the like, a function of controlling a process with avariety of types of software (programs), a wireless communicationfunction, a function of connecting to a variety of computer networkswith a wireless communication function, a function of transmitting andreceiving a variety of data with a wireless communication function, afunction of reading a program or data stored in a recording medium anddisplaying the program or data on the display portion, and the like.Furthermore, the electronic device including a plurality of displayportions can have a function of displaying image data mainly on onedisplay portion while displaying text data on another display portion, afunction of displaying a three-dimensional image by displaying images ona plurality of display portions with a parallax taken into account, orthe like. Furthermore, the electronic device including an imagereceiving portion can have a function of taking a still image, afunction of taking a moving image, a function of automatically ormanually correcting a taken image, a function of storing a taken imagein a recording medium (an external recording medium or a recordingmedium incorporated in the camera), a function of displaying a takenimage on the display portion, or the like. Note that functions that canbe provided for the electronic devices illustrated in FIGS. 4A to 4F arenot limited to those described above, and the electronic devices canhave a variety of functions.

FIG. 4G illustrates a smart watch, which includes the housing 7000, thedisplay portion 7001, operation buttons 7022 and 7023, a connectionterminal 7024, a band 7025, a clasp 7026, and the like.

The display portion 7001 mounted in the housing 7000 serving as a bezelincludes a non-rectangular display region. The display portion 7001 candisplay an icon 7027 indicating time, another icon 7028, and the like.The display portion 7001 may be a touch panel (an input/output device)including a touch sensor (an input device).

The smart watch illustrated in FIG. 4G can have a variety of functions,such as a function of displaying a variety of information (e.g., a stillimage, a moving image, and a text image) on the display portion, a touchpanel function, a function of displaying a calendar, date, time, and thelike, a function of controlling processing with a variety of types ofsoftware (programs), a wireless communication function, a function ofconnecting to a variety of computer networks with a wirelesscommunication function, a function of transmitting and receiving avariety of data with a wireless communication function, a function ofreading a program or data stored in a recording medium and displayingthe program or data on the display portion, and the like.

The housing 7000 can include a speaker, a sensor (a sensor having afunction of measuring or sensing force, displacement, position, speed,acceleration, angular velocity, rotational frequency, distance, light,liquid, magnetism, temperature, chemical substance, sound, time,hardness, electric field, current, voltage, electric power, radiation,flow rate, humidity, gradient, oscillation, odor, or infrared rays), amicrophone, and the like.

Note that the light-emitting device of one embodiment of the presentinvention or the display device including the light-emitting element ofone embodiment of the present invention can be used in the displayportion of each electronic device described in this embodiment, enablingdisplay with high color purity.

Another electronic device including the light-emitting device is afoldable portable information terminal illustrated in FIGS. 5A to 5C.FIG. 5A illustrates a portable information terminal 9310 which isopened. FIG. 5B illustrates the portable information terminal 9310 whichis being opened or being folded. FIG. 5C illustrates the portableinformation terminal 9310 which is folded. The portable informationterminal 9310 is highly portable when folded. The portable informationterminal 9310 is highly browsable when opened because of a seamlesslarge display region.

A display portion 9311 is supported by three housings 9315 joinedtogether by hinges 9313. Note that the display portion 9311 may be atouch panel (an input/output device) including a touch sensor (an inputdevice). By bending the display portion 9311 at a connection portionbetween two housings 9315 with the use of the hinges 9313, the portableinformation terminal 9310 can be reversibly changed in shape from anopened state to a folded state. The light-emitting device of oneembodiment of the present invention can be used for the display portion9311. In addition, display with high color purity can be performed. Adisplay region 9312 in the display portion 9311 is a display region thatis positioned at a side surface of the portable information terminal9310 which is folded. On the display region 9312, information icons,file shortcuts of frequently used applications or programs, and the likecan be displayed, and confirmation of information and start ofapplication and the like can be smoothly performed.

FIGS. 6A and 6B illustrate an automobile including the light-emittingdevice. The light-emitting device can be incorporated in the automobile,and specifically, can be included in lights 5101 (including lights ofthe rear part of the car), a wheel cover 5102, a part or whole of a door5103, or the like on the outer side of the automobile which isillustrated in FIG. 6A. The light-emitting device can also be includedin a display portion 5104, a steering wheel 5105, a gear lever 5106, aseat 5107, an inner rearview mirror 5108, or the like on the inner sideof the automobile which is illustrated in FIG. 6B, or in a part of aglass window.

As described above, the electronic devices and automobiles can beobtained using the light-emitting device or the display device of oneembodiment of the present invention. In that case, display with highcolor purity can be performed. Note that the light-emitting device orthe display device can be used for electronic devices and automobiles ina variety of fields without being limited to those described in thisembodiment.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 6

In this embodiment, a structure of a lighting device fabricated usingthe light-emitting device of one embodiment of the present invention orthe light-emitting element which is a part of the light-emitting deviceis described with reference to FIGS. 7A to 7D.

FIGS. 7A to 7D are examples of cross-sectional views of lightingdevices. FIGS. 7A and 7B illustrate bottom-emission lighting devices inwhich light is extracted from the substrate side, and FIGS. 7C and 7Dillustrate top-emission lighting devices in which light is extractedfrom the sealing substrate side.

A lighting device 4000 illustrated in FIG. 7A includes a light-emittingelement 4002 over a substrate 4001. In addition, the lighting device4000 includes a substrate 4003 with unevenness on the outside of thesubstrate 4001. The light-emitting element 4002 includes a firstelectrode 4004, an EL layer 4005, and a second electrode 4006.

The first electrode 4004 is electrically connected to an electrode 4007,and the second electrode 4006 is electrically connected to an electrode4008. In addition, an auxiliary wiring 4009 electrically connected tothe first electrode 4004 may be provided. Note that an insulating layer4010 is formed over the auxiliary wiring 4009.

The substrate 4001 and a sealing substrate 4011 are bonded to each otherwith a sealant 4012. A desiccant 4013 is preferably provided between thesealing substrate 4011 and the light-emitting element 4002. Thesubstrate 4003 has the unevenness illustrated in FIG. 7A, whereby theextraction efficiency of light emitted from the light-emitting element4002 can be increased.

Instead of the substrate 4003, a diffusion plate 4015 may be provided onthe outside of the substrate 4001 as in a lighting device 4100illustrated in FIG. 7B.

A lighting device 4200 illustrated in FIG. 7C includes a light-emittingelement 4202 over a substrate 4201. The light-emitting element 4202includes a first electrode 4204, an EL layer 4205, and a secondelectrode 4206.

The first electrode 4204 is electrically connected to an electrode 4207,and the second electrode 4206 is electrically connected to an electrode4208. An auxiliary wiring 4209 electrically connected to the secondelectrode 4206 may be provided. An insulating layer 4210 may be providedunder the auxiliary wiring 4209.

The substrate 4201 and a sealing substrate 4211 with unevenness arebonded to each other with a sealant 4212. A barrier film 4213 and aplanarization film 4214 may be provided between the sealing substrate4211 and the light-emitting element 4202. The sealing substrate 4211 hasthe unevenness illustrated in FIG. 7C, whereby the extraction efficiencyof light emitted from the light-emitting element 4202 can be increased.

Instead of the sealing substrate 4211, a diffusion plate 4215 may beprovided over the light-emitting element 4202 as in a lighting device4300 illustrated in FIG. 7D.

Note that with the use of the light-emitting device of one embodiment ofthe present invention or the light-emitting element which is a part ofthe light-emitting device as described in this embodiment, a lightingdevice having desired chromaticity can be provided.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 7

In this embodiment, application examples of lighting devices fabricatedusing the light-emitting device of one embodiment of the presentinvention or the light-emitting element which is a part of thelight-emitting device will be described with reference to FIG. 8 .

A ceiling light 8001 can be used as an indoor lighting device. Examplesof the ceiling light 8001 include a direct-mount light and an embeddedlight. Such a lighting device is fabricated using the light-emittingdevice and a housing or a cover in combination. Besides, application toa cord pendant light (light that is suspended from a ceiling by a cord)is also possible.

Afoot light 8002 lights a floor so that safety on the floor can beimproved. For example, it can be effectively used in a bedroom, on astaircase, or on a passage. In that case, the size or shape of the footlight can be changed depending on the area or structure of a room. Thefoot light 8002 can be a stationary lighting device fabricated using thelight-emitting device and a support base in combination.

A sheet-like lighting 8003 is a thin sheet-like lighting device. Thesheet-like lighting, which is attached to a wall when used, isspace-saving and thus can be used for a wide variety of uses.Furthermore, the area of the sheet-like lighting can be increased. Thesheet-like lighting can also be used on a wall or housing having acurved surface.

In addition, a lighting device 8004 in which the direction of light froma light source is controlled to be only a desired direction can be used.

Besides the above examples, when the light-emitting device of oneembodiment of the present invention or the light-emitting element whichis a part of the light-emitting device is used as part of furniture in aroom, a lighting device that functions as the furniture can be obtained.

As described above, a variety of lighting devices that include thelight-emitting device can be obtained. Note that these lighting devicesare also embodiments of the present invention.

The structures described in this embodiment can be combined with any ofthe structures described in the other embodiments as appropriate.

Example 1 Synthesis Example 1

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis(N-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6chBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (100) in Embodiment 1, is described. The structure of1,6chBnfAPrn is shown below.

Step 1: Synthesis of 3-cyclohexyl-2-methoxynaphthalene

Into a 1 L three-neck flask were put 8.9 g (37 mmol) of2-bromo-3-methoxynaphthalene and 0.53 g (1.1 mmol) of2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (abbreviation:XPhos), and the air in the flask was replaced with nitrogen. Then, 94 mLof tetrahydrofuran (abbreviation: TIF) was added, and the resultingmixture was degassed under reduced pressure and then stirred at 70° C.To this mixture was added 0.51 g (0.56 mmol) oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and100 mL of cyclohexylmagnesium bromide (a 1.0 mol/L tetrahydrofuransolution, 0.10 mol) was dropped into the mixture; then, the resultingmixture was stirred for 6 hours at 70° C. under a nitrogen stream.

After the stirring, this mixture was dropped into 0° C. hydrochloricacid (1 mol/L), and an aqueous layer of the resulting mixture wassubjected to extraction using toluene. The obtained solution of theextract and an organic layer were combined, and the mixture was washedwith water and saturated brine. Then, the mixture was dried withmagnesium sulfate. The mixture was separated by gravity filtration, andthe obtained filtrate was concentrated to give a yellow oily substance.

The obtained oily substance was purified by silica gel columnchromatography (a developing solvent was a mixed solvent oftoluene:hexane=9:1) to give 6.5 g of a target white solid in a yield of73%. A synthesis scheme of Step 1 is shown in (a-1).

Step 2: Synthesis of 3-cyclohexyl-2-naphthol

Into a 500 mL three-neck flask was put 6.5 g (27 mmol) of3-cyclohexyl-2-methoxynaphthalene, and the air in the flask was replacedwith nitrogen. Then, 140 mL of dichloromethane was added, and theresulting solution was stirred at 0° C. Into the solution, 55 mL ofboron tribromide (a 1.0 mol/L dichloromethane solution, 55 mmol) wasdropped; then, the resulting solution was stirred for 15 hours while thetemperature was returned to room temperature.

After the stirring, this mixture was dropped into a 0° C. saturatedaqueous solution of sodium hydrogencarbonate, and an aqueous layer ofthe resulting mixture was subjected to extraction using dichloromethane.The obtained solution of the extract and an organic layer were combined,and the mixture was washed with water and saturated brine. Then, themixture was dried with magnesium sulfate. The mixture was separated bygravity filtration, and the obtained filtrate was concentrated to give5.9 g of a target yellowish white solid in a yield of 96%. A synthesisscheme of Step 2 is shown in (a-2).

Results of nuclear magnetic resonance (H NMR) spectroscopy analysis ofthe yellowish white solid obtained in Step 2 are shown below. Theresults reveal that 3-cyclohexyl-2-naphthol was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=7.74 (d, J=8.3 Hz, 1H), 7.63-7.61 (m, 2H),7.39-7.26 (m, 2H), 7.07 (s, 1H), 4.93 (s, 1H), 2.99-2.91 (m, 1H),1.99-1.78 (m, 5H), 1.54-1.25 (m, 5H).

Step 3: Synthesis of 6-cyclohexylbenzo[b]naphtho[1,2-d]furan

Into a 500 mL three-neck flask were put 5.9 g (26 mmol) of3-cyclohexyl-2-naphthol, 9.2 g (52 mmol) of 2-bromofluorobenzene, and 17g (52 mmol) of cesium carbonate, and the air in the flask was replacedwith nitrogen. Then, 130 mL of N-methyl-2-pyrrolidone (abbreviation:NMP) was added and the resulting solution was degassed under reducedpressure and then stirred for 6.5 hours at 180° C. under a nitrogenstream.

After the stirring, 10 g (31 mmol) of cesium carbonate and 0.7 g (2.7mmol) of triphenylphosphine were added to this mixture. The resultingmixture was degassed by being stirred under reduced pressure. To thismixture was added 0.30 g (1.3 mmol) of palladium(II) acetate, and theresulting mixture was stirred for 6 hours at 180° C. under a nitrogenstream.

After the stirring, water was added to this mixture, and an aqueouslayer was subjected to extraction using ethyl acetate. The obtainedsolution of the extract and an organic layer were combined, and themixture was washed with water and saturated brine. Then, the mixture wasdried with magnesium sulfate. The mixture was separated by gravityfiltration, and the obtained filtrate was concentrated to give a brownoily substance. The obtained oily substance was purified by silica gelcolumn chromatography (a developing solvent: hexane) to give 7.0 g of atarget white solid in a yield of 89%. A synthesis scheme of Step 3 isshown in (a-3).

Results of nuclear magnetic resonance (¹H NMR) spectroscopy analysis ofthe white solid obtained in Step 3 are shown below. The results revealthat 6-cyclohexylbenzo[b]naphtho[1,2-d]furan was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.60 (d, J=8.3 Hz, 1H), 8.41-8.38 (m, 1H),7.99 (d, J=7.8 Hz, 1H), 7.74-7.71 (m, 2H), 7.68-7.63 (m, 1H), 7.54-7.46(m, 3H), 3.38-3.28 (m, 1H), 2.17-1.38 (m, 10H).

Step 4: Synthesis of 6-cyclohexyl-8-iodobenzo[b]naphtho[1,2-d]furan

Into a 300 mL three-neck flask was put 3.1 g (10 mmol) of6-cyclohexylbenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 75 mL of tetrahydrofuran was added, andthe mixture was stirred at −80° C. Into this solution was dropped 7.2 mL(12 mmol) of n-butyllithium (a 1.6 mol/L n-hexane solution), thetemperature was returned to room temperature, and the mixture wasstirred for 2 hours under a nitrogen stream. After the stirring, thetemperature of the resulting mixture was reduced to −80° C.; then, asolution of 5.3 g (21 mmol) of iodine in 20 mL of tetrahydrofuran wasadded to the mixture, and stirring was performed for 15 hours while thetemperature was gradually returned to room temperature.

After the stirring, an aqueous solution of sodium thiosulfate was addedto this mixture, and an aqueous layer was subjected to extraction usingethyl acetate. The obtained solution of the extract and an organic layerwere combined, and the mixture was washed with water and saturatedbrine. Then, the mixture was dried with magnesium sulfate. The mixturewas separated by gravity filtration, and the obtained filtrate wasconcentrated to give a brown oily substance.

The obtained compound was purified by silica gel column chromatography(a developing solvent: hexane) to give 3.6 g of a target white solid. Asynthesis scheme of Step 4 is shown in (a-4).

Results of nuclear magnetic resonance (1H NMR) spectroscopy analysis ofthe white solid obtained in Step 4 are shown below. The results revealthat 6-cyclohexyl-8-iodobenzo[b]naphtho[1,2-d]furan was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.54 (d, J=8.3 Hz, 1H), 8.36-8.33 (m, 1H),7.99 (d, J=7.8 Hz, 1H), 7.86-7.83 (m, 1H), 7.76 (s, 1H), 7.69-7.61 (m,1H), 7.56-7.50 (m, 1H), 7.25 (t, J=7.8 Hz, 1H), 3.37-3.28 (m, 1H),2.18-1.38 (m, 10H).

By ¹H NMR analysis, the obtained6-cyclohexyl-8-iodobenzo[b]naphtho[1,2-d]furan was found to contain 18%6-cyclohexylbenzo[b]naphtho[1,2-d]furan, the raw material, according tothe NMR ratio.

Step 5: Synthesis ofN-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine

Into a 100 mL three-neck flask were put 1.7 g (3.9 mmol) of6-cyclohexyl-8-iodobenzo[b]naphtho[1,2-d]furan (which contained 18%6-cyclohexylbenzo[b]naphtho[1,2-d]furan according to the NMR ratio)obtained in Step 4, 0.44 g (4.7 mmol) of aniline, and 1.1 g (12 mmol) ofsodium t-butoxide, and the air in the flask was replaced with nitrogen.To this mixture was added 20 mL of toluene, and the resulting mixturewas degassed under reduced pressure. To this mixture were added 0.30 mL(0.35 mmol) of tri(tert-butyl)phosphine (a 10 wt % hexane solution) and40 mg (70 μmol) of bis(dibenzylideneacetone)palladium(0) and then,stirring was performed for 7 hours at 80° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown solid.

This solid was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give1.2 g of a target white solid in a yield of 82%. In addition, 0.20 g of6-cyclohexylbenzo[b]naphtho[1,2-d]furan was collected. A synthesisscheme of Step 5 is shown in (a-5).

Results of nuclear magnetic resonance (¹H NMR) spectroscopy analysis ofthe white solid obtained in Step 5 are shown below. In addition, ¹H NMRcharts are shown in FIGS. 9A to 9C. Note that FIG. 9B is an enlargedchart showing the range of 6.0 ppm to 9.0 ppm in FIG. 9A. FIG. 9C is anenlarged chart showing the range of 1.0 ppm to 3.5 ppm in FIG. 9A. Theresults reveal thatN-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.59 (d, J=8.3 Hz, 1H), 7.98-7.92 (m, 2H),7.72 (s, 1H), 7.67-7.62 (m, 1H), 7.54-7.48 (m, 1H), 7.39-7.25 (m, 6H),7.05-6.99 (m, 1H), 6.25 (s, 1H), 3.35-3.25 (m, 1H), 2.13-1.31 (m, 10H).

Step 6: Synthesis of 1,6chBnfAPrn

Into a 200 mL three-neck flask were put 0.79 g (2.2 mmol) of1,6-dibromopyrene, 1.7 g (4.4 mmol) ofN-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine, 0.84 g (8.7mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 22 mL of xylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 7 hours at 140° C. under a nitrogenstream.

After the stirring, 500 mL of toluene was added and heating wasperformed; then, hot filtration was performed through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina. A yellow solid obtained by concentration of the resultingfiltrate was purified by silica gel column chromatography (a developingsolvent was a mixed solvent of hexane and toluene, and the ratio ofhexane to toluene was changed from 9:1 to 7:3 to form a gradient) togive a target yellow solid. The obtained yellow solid was recrystallizedwith toluene to give 1.2 g of a target yellow solid in a yield of 56%.

By a train sublimation method, 1.2 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 320° C. under a pressure of 2.0×10⁻² Pa for 6 hours.After the purification by sublimation, 0.92 g of a target yellow solidwas obtained at a collection rate of 76%. A synthesis scheme of Step 6is shown in (a-6).

Results of nuclear magnetic resonance (H NMR) spectroscopy analysis ofthe yellow solid obtained in Step 6 are shown below. In addition, ¹H NMRcharts are shown in FIGS. 10A to 10C. Note that FIG. 10B is an enlargedchart showing the range of 6.5 ppm to 9.0 ppm in FIG. 10A. FIG. 10C isan enlarged chart showing the range of 0.5 ppm to 3.0 ppm in FIG. 10A.The results reveal that 1,6chBnfAPrn (Structural Formula (100)) wasobtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.59 (d, J=8.3 Hz, 2H), 8.27 (d, J=8.8 Hz,2H), 8.13-8.10 (m, 2H), 8.06 (d, J=8.1 Hz, 2H), 7.92-7.85 (m, 6H),7.67-7.61 (m, 2H), 7.54-7.47 (m, 4H), 7.37 (t, J=7.8 Hz, 2H), 7.24-7.16(m, 6H), 7.03-6.96 (m, 6H), 2.51-2.41 (m, 2H), 1.48-0.74 (m, 20H).

Next, ultraviolet-visible absorption spectra (hereinafter simplyreferred to as “absorption spectra”) and emission spectra of a toluenesolution and a solid thin film of 1,6chBnfAPrn were measured. The solidthin film was formed over a quartz substrate by a vacuum evaporationmethod. The absorption spectra were measured using UV-visiblespectrophotometers (solution: V-550 manufactured by JASCO Corporation,thin film: U-4100 manufactured by Hitachi High-TechnologiesCorporation). Note that the absorption spectrum of the solution wascalculated by subtraction of the measured absorption spectrum of onlytoluene in a quartz cell, and the absorption spectrum of the thin filmwas calculated using an absorbance (−log₁₀ [% T/(100−% R)]) obtainedfrom a transmittance and a reflectance of the substrate and the thinfilm. Note that % T represents transmittance and % R representsreflectance. The emission spectra were measured using a fluorescencespectrophotometer (FS920 manufactured by Hamamatsu Photonics K.K.).

FIG. 11A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 11B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 11A, the toluene solution of1,6chBnfAPrn exhibited an absorption peak at around 425 nm and anemission wavelength peak at 450 nm (excitation wavelength: 415 nm).Furthermore, as shown by the results in FIG. 11B, the solid thin film of1,6chBnfAPrn exhibited an absorption peak at around 425 nm and emissionwavelength peaks at around 498 nm and 460 nm (excitation wavelength: 400nm).

Furthermore, differential scanning calorimetry (DSC) measurement wasperformed on 1,6chBnfAPrn by Pyris1DSC manufactured by PerkinElmer, Inc.In the differential scanning calorimetry measurement, the temperaturewas raised from −10° C. to 370° C. at a temperature rising rate of 50°C./min, kept for 1 minute, lowered to −10° C. at a temperaturedecreasing rate of 100° C./min, raised from −10° C. to 370° C. at atemperature rising rate of 10° C./min, kept for 1 minute, and thenlowered to −10° C. at a temperature decreasing rate of 10° C./min. Nopeak was observed in the DSC measurement results during the secondtemperature rise; from the DSC measurement results during the firsttemperature rise, the melting point of 1,6chBnfAPrn was found to be 354°C.

Thermogravimetry-differential thermal analysis (TG-DTA) was performed on1,6chBnfAPrn. The measurement was performed using a high vacuumdifferential type differential thermal balance (TG-DTA2410SA,manufactured by Bruker AXS K.K.). The measurement was performed at 10 Paat a temperature rising rate of 10° C./min under a nitrogen stream (aflow rate of 3.5 mL/min). The thermogravimetry-differential thermalanalysis showed that the temperature (decomposition temperature) atwhich the weight measured by thermogravimetry becomes −5% of the weightat the start of the measurement is 338° C., which means sublimation at arelatively low temperature (350° C.).

Example 2 Synthesis Example 2

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis[N-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine](abbreviation: 1,6oMechBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (101) in Embodiment 1, is described. The structure of1,6oMechBnfAPrn is shown below.

The method for synthesizing 1,6oMechBnfAPrn described in this exampleand the method for synthesizing 1,6chBnfAPrn described in Example 1share Steps 1 to 4 (synthesis of6-cyclohexyl-8-iodobenzo[b]naphtho[1,2-d]furan). Example 1 can bereferred to for the common Steps 1 to 4; the subsequent Steps 7 and 8are described in this example.

Step 7: Synthesis ofN-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine

Into a 100 mL three-neck flask were put 1.1 g (2.6 mmol) of6-cyclohexyl-8-iodobenzo[b]naphtho[1,2-d]furan, 0.33 g (3.1 mmol) ofo-toluidine, and 0.74 g (7.7 mmol) of sodium t-butoxide, and the air inthe flask was replaced with nitrogen. To this mixture was added 13 mL oftoluene, and the resulting mixture was degassed under reduced pressure.To this mixture were added 0.30 mL (0.35 mmol) oftri(tert-butyl)phosphine (a 10 wt % hexane solution) and 40 mg (70 μmol)of bis(dibenzylideneacetone)palladium(0) and then, stirring wasperformed for 4 hours at 80° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown solid.

This solid was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give0.64 g of a target white solid in a yield of 61%. A synthesis scheme ofStep 7 is shown in (a-7).

Results of nuclear magnetic resonance (¹H NMR) spectroscopy analysis ofthe white solid obtained in Step 7 are shown below. In addition, ¹H NMRcharts are shown in FIGS. 12A to 12C. Note that FIG. 12B is an enlargedchart showing the range of 6.0 ppm to 9.0 ppm in FIG. 12A. FIG. 12C isan enlarged chart showing the range of 1.0 ppm to 3.5 ppm in FIG. 12A.The results reveal thatN-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine wasobtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.60 (d, J=8.3 Hz, 1H), 7.99 (d, J=7.8 Hz,1H), 7.92-7.90 (m, 1H), 7.73 (s, 1H), 7.68-7.62 (m, 1H), 7.55-7.50 (m,1H), 7.41 (d, J=7.8 Hz, 1H), 7.36-7.28 (m, 2H), 7.23-7.13 (m, 2H),7.05-7.00 (m, 1H), 6.01 (bs, 1H), 3.31-3.24 (m, 1H), 2.42 (s, 3H),2.15-1.33 (m, 10H).

Step 8: Synthesis of 1,6oMechBnfAPrn

Into a 200 mL three-neck flask were put 1.5 g (4.1 mmol) of1,6-dibromopyrene, 3.3 g (8.2 mmol) ofN-(2-methylphenyl)-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine, 1.6g (16 mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 42 mL of xylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 6.5 hours at 140° C. under a nitrogenstream.

After the stirring, 500 mL of toluene was added and heating wasperformed; then, hot filtration was performed through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina. A yellow solid obtained by concentration of the resultingfiltrate was purified by silica gel column chromatography (a developingsolvent was a mixed solvent of hexane and toluene, and the ratio ofhexane to toluene was changed from 9:1 to 7:3 to form a gradient) togive a target yellow solid. The obtained yellow solid was recrystallizedwith toluene to give 1.0 g of a target yellow solid in a yield of 24%.

By a train sublimation method, 1.0 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 315° C. under a pressure of 2.0×10⁻² Pa for 6 hours.After the purification by sublimation, 0.92 g of a target yellow solidwas obtained at a collection rate of 92%. A synthesis scheme of Step 8is shown in (a-8).

Results of nuclear magnetic resonance (H NMR) spectroscopy analysis ofthe yellow solid obtained in Step 8 are shown below. In addition, ¹H NMRcharts are shown in FIGS. 13A to 13C. Note that FIG. 13B is an enlargedchart showing the range of 6.5 ppm to 9.0 ppm in FIG. 13A. FIG. 13C isan enlarged chart showing the range of 0.5 ppm to 3.0 ppm in FIG. 13A.The results reveal that 1,6oMechBnfAPrn (Structural Formula (101)) wasobtained.

¹H NMR (CDCl₃, 60° C., 300 MHz): σ=8.58 (d, J=8.3 Hz, 2H), 8.09-8.04 (m,4H), 7.95-7.89 (m, 4H), 7.80 (d, J=9.3 Hz, 2H), 7.67-7.60 (m, 4H),7.51-7.45 (m, 4H), 7.32-7.24 (m, 4H), 7.16-7.07 (m, 6H), 6.85-6.82 (m,2H), 2.46-2.40 (m, 2H), 2.20 (s, 6H), 1.51-0.84 (m, 20H).

Next, absorption spectra and emission spectra of a toluene solution anda solid thin film of 1,6oMechBnfAPrn were measured. The solid thin filmwas formed over a quartz substrate by a vacuum evaporation method. Theabsorption spectra were measured using UV-visible spectrophotometers(solution: V-550 manufactured by JASCO Corporation, thin film: U-4100manufactured by Hitachi High-Technologies Corporation). Note that theabsorption spectrum of the solution was calculated by subtraction of themeasured absorption spectrum of only toluene in a quartz cell, and theabsorption spectrum of the thin film was calculated using an absorbance(−log₁₀ [% T/(100−% R)]) obtained from a transmittance and a reflectanceof the substrate and the thin film. Note that % T representstransmittance and % R represents reflectance. The emission spectra weremeasured using a fluorescence spectrophotometer (FS920 manufactured byHamamatsu Photonics K.K.).

FIG. 14A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 14B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 14A, the toluene solution of1,6oMechBnfAPrn exhibited an absorption peak at around 424 nm and anemission wavelength peak at 448 nm (excitation wavelength: 415 nm).Furthermore, as shown by the results in FIG. 14B, the solid thin film of1,6oMechBnfAPrn exhibited an absorption peak at around 428 nm andemission wavelength peaks at around 493 nm and 457 nm (excitationwavelength: 400 nm).

Example 3 Synthesis Example 3

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis(N-phenyl-6-isopropylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6iPrBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (116) in Embodiment 1, andN,N′-(pyrene-1,6-diyl)bis(N-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6nPrBnfAPrn) represented by Structural Formula (118) isdescribed. The structures of 1,6iPrBnfAPrn and 1,6nPrBnfAPrn are shownbelow.

Step 1: Synthesis of 3-isopropyl-2-methoxynaphthalene

Into a 1 L three-neck flask were put 3.5 g (15 mmol) of2-bromo-3-methoxynaphthalene and 0.21 g (0.44 mmol) of2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (abbreviation:XPhos), and the air in the flask was replaced with nitrogen. Then, 60 mLof tetrahydrofuran (abbreviation: TIF) was added, and the resultingmixture was degassed under reduced pressure and then stirred at 70° C.To this mixture was added 0.20 g (0.22 mmol) oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and22 mL of cyclohexylmagnesium bromide (a 2.0 mol/L tetrahydrofuransolution, 44 mmol) was dropped into the mixture; then, this mixture wasstirred for 6 hours at 70° C. under a nitrogen stream.

After the stirring, this mixture was dropped into 0° C. hydrochloricacid (1 mol/L), and an aqueous layer of the resulting mixture wassubjected to extraction using toluene. The obtained solution of theextract and an organic layer were combined, and the mixture was washedwith water and saturated brine. Then, the mixture was dried withmagnesium sulfate. The mixture was separated by gravity filtration, andthe obtained filtrate was concentrated to give a yellow oily substance.

The obtained oily substance was purified by silica gel columnchromatography (a developing solvent: hexane) to give 2.5 g of a whitesolid in a yield of 75%. A synthesis scheme of Step 1 is shown in (b-1).

The white solid obtained in Step 1 was analyzed by nuclear magneticresonance (H NMR) spectroscopy. The results revealed that a mixture of3-isopropyl-2-methoxynaphthalene and 3-normalpropyl-2-methoxynaphthalenewas obtained.

The above ¹H NMR analysis showed that 3-isopropyl-2-methoxynaphthaleneand 3-normalpropyl-2-methoxynaphthalene were generated in a ratio of18:82.

Step 2: Synthesis of 3-isopropyl-2-naphthol and3-normalpropyl-2-naphthol

Into a 300 mL three-neck flask were put 2.5 g (13 mmol) of a mixture of3-isopropyl-2-methoxynaphthalene and3-normalpropyl-2-methoxynaphthalene, and the air in the flask wasreplaced with nitrogen. Then, 65 mL of dichloromethane was added, andthe resulting solution was stirred at 0° C. Into the solution, 26 mL ofboron tribromide (a 1.0 mol/L dichloromethane solution, 26 mmol) wasdropped; then, the resulting solution was stirred for 15 hours while thetemperature was returned to room temperature.

After the stirring, this mixture was dropped into a 0° C. saturatedaqueous solution of sodium hydrogencarbonate, and an aqueous layer ofthe resulting mixture was subjected to extraction using dichloromethane.The obtained solution of the extract and an organic layer were combined,and the mixture was washed with water and saturated brine. Then, themixture was dried with magnesium sulfate. The mixture was separated bygravity filtration, and the obtained filtrate was concentrated to give2.3 g of a target yellowish white solid in a yield of 98%. A synthesisscheme of Step 2 is shown in (b-2).

The yellowish white solid obtained in Step 2 was analyzed by nuclearmagnetic resonance (¹H NMR) spectroscopy. The results revealed that anaphthol compound was obtained.

Step 3: Synthesis of 6-isopropylbenzo[b]naphtho[1,2-d]furan and6-normalpropylbenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask were put 2.3 g (12 mmol) of a mixture of3-isopropyl-2-naphthol and 3-normalpropyl-2-naphthol, 4.3 g (25 mmol) of2-bromofluorobenzene, and 8.0 g (25 mmol) of cesium carbonate, and theair in the flask was replaced with nitrogen. Then, 62 mL ofN-methyl-2-pyrrolidone (abbreviation: NMP) was added and the resultingsolution was degassed under reduced pressure and then stirred for 7hours at 180° C. under a nitrogen stream.

After the stirring, 7.2 g (22 mmol) of cesium carbonate and 0.30 g (1.1mmol) of triphenylphosphine were added to this mixture. The resultingmixture was degassed by being stirred under reduced pressure. To thismixture was added 0.13 g (0.58 mmol) of palladium(II) acetate, and theresulting mixture was stirred for 7 hours at 180° C. under a nitrogenstream.

After the stirring, water was added to this mixture, and an aqueouslayer was subjected to extraction using ethyl acetate. The obtainedsolution of the extract and an organic layer were combined, and themixture was washed with water and saturated brine. Then, the mixture wasdried with magnesium sulfate. The mixture was separated by gravityfiltration, and the obtained filtrate was concentrated to give a brownoily substance. The obtained oily substance was purified by silica gelcolumn chromatography (a developing solvent: hexane) to give 2.7 g of atarget white solid in a yield of 84%. A synthesis scheme of Step 3 isshown in (b-3).

The white solid obtained in Step 3 was analyzed by nuclear magneticresonance (H NMR) spectroscopy. The results revealed that abenzo[b]naphtho[1,2-d]furan compound was obtained.

Step 4: Synthesis of 6-isopropyl-8-iodobenzo[b]naphtho[1,2-d]furan and6-normalpropyl-8-iodobenzo[b]naphtho[1,2-d]furan

Into a 300 mL three-neck flask was put 2.7 g (10 mmol) of a mixture of6-isopropylbenzo[b]naphtho[1,2-d]furan and6-normalpropylbenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 75 mL of tetrahydrofuran was added, andthe mixture was stirred at −80° C. Into this solution was dropped 7.2 mL(12 mmol) of n-butyllithium (a 1.6 mol/L n-hexane solution), thetemperature was returned to room temperature, and the mixture wasstirred for 2 hours under a nitrogen stream. After the stirring, thetemperature of the resulting mixture was reduced to −80° C.; then, asolution of 5.3 g (21 mmol) of iodine in 20 mL of tetrahydrofuran wasadded to the mixture, and stirring was performed for 15 hours while thetemperature was gradually returned to room temperature.

After the stirring, an aqueous solution of sodium thiosulfate was addedto this mixture, and an aqueous layer was subjected to extraction usingethyl acetate. The obtained solution of the extract and an organic layerwere combined, and the mixture was washed with water and saturatedbrine. Then, the mixture was dried with magnesium sulfate. The mixturewas separated by gravity filtration, and the obtained filtrate wasconcentrated to give a brown oily substance.

The obtained compound was purified by silica gel column chromatography(a developing solvent: hexane) to give 3.2 g of a target white solid. Asynthesis scheme of Step 4 is shown in (b-4).

The white solid obtained in Step 4 was analyzed by nuclear magneticresonance (H NMR) spectroscopy. The results revealed that an8-iodobenzo[b]naphtho[1,2-d]furan compound was obtained.

The ¹H NMR analysis revealed that a mixture of a target iodide and a rawmaterial was obtained. The NMR ratio of the iodide to the raw materialwas 87:13.

Step 5: Synthesis ofN-phenyl-6-isopropylbenzo[b]naphtho[1,2-d]furan-8-amine andN-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine

Into a 100 mL three-neck flask were put 1.6 g (4.1 mmol) of a mixture of6-isopropyl-8-iodobenzo[b]naphtho[1,2-d]furan and6-normalpropyl-8-iodobenzo[b]naphtho[1,2-d]furan, 0.47 g (5.1 mmol) ofaniline, and 1.2 g (13 mmol) of sodium t-butoxide, and the air in theflask was replaced with nitrogen. To this mixture was added 21 mL oftoluene, and the resulting mixture was degassed under reduced pressure.To this mixture were added 0.30 mL (0.35 mmol) oftri(tert-butyl)phosphine (a 10 wt % hexane solution) and 40 mg (70 μmol)of bis(dibenzylideneacetone)palladium(0) and then, stirring wasperformed for 5.5 hours at 80° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown oily substance.

This oily substance was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give1.1 g of a target colorless oily substance in a yield of 78%. Asynthesis scheme of Step 5 is shown in (b-5).

The colorless oily substance obtained in Step 5 was analyzed by nuclearmagnetic resonance (¹H NMR) spectroscopy. In addition, ¹H NMR charts areshown in FIGS. 15A to 15C. Note that FIG. 15B is an enlarged chartshowing the range of 6.5 ppm to 9.0 ppm in FIG. 15A. FIG. 15C is anenlarged chart showing the range of 0.5 ppm to 4.0 ppm in FIG. 15A. Theresults reveal that a mixture ofN-phenyl-6-isopropylbenzo[b]naphtho[1,2-d]furan-8-amine andN-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.60-8.58 (m, 1H), 8.00-7.92 (m, 2H),7.75-7.63 (m, 2H), 7.55-7.50 (m, 1H), 7.42-7.27 (m, 6H), 7.65-7.01 (m,1H), 3.72-3.68 (m, 1H (iPr)), 3.13 (t, J=7.6 Hz, 2H (nPr)), 1.93 (sext,J=7.4 Hz, 2H (nPr)), 1.52 (d, J=6.8 Hz, 6H (iPr)), 1.08 (t, J=7.6 Hz, 3H(nPr)).

Step 6: Synthesis of 1,6iPrBnfAPrn and 1,6nPrBnfAPrn

Into a 100 mL three-neck flask were put 0.36 g (1.0 mmol) of1,6-dibromopyrene, 0.71 g (2.0 mmol) of a mixture ofN-phenyl-6-isopropylbenzo[b]naphtho[1,2-d]furan-8-amine andN-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine, 0.40 g (4.2mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 10 mL of xylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 6.5 hours at 140° C. under a nitrogenstream.

After the stirring, 500 mL of toluene was added and heating wasperformed; then, hot filtration was performed through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina. A yellow solid obtained by concentration of the resultingfiltrate was recrystallized with toluene to give 0.43 g of a targetyellow solid in a yield of 48%.

By a train sublimation method, 1.2 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 327° C. under a pressure of 2.0×10⁻² Pa for 4 hours.After the purification by sublimation, 0.32 g of a target yellow solidwas obtained at a collection rate of 75%. A synthesis scheme of Step 6is shown in (b-6).

The yellow solid obtained in Step 6 was analyzed by nuclear magneticresonance (H NMR) spectroscopy. In addition, ¹H NMR charts are shown inFIGS. 16A to 16C. Note that FIG. 16B is an enlarged chart showing therange of 6.5 ppm to 9.0 ppm in FIG. 16A. FIG. 16C is an enlarged chartshowing the range of 0 ppm to 4.0 ppm in FIG. 16A. The results revealedthat 1,6iPrBnfAPrn (Structural Formula (116)) and 1,6nPrBnfAPrn(Structural Formula (118)) were obtained. A compound represented byStructural Formula (144) was probably generated as well.

Example 4

In this example, element structures, fabrication methods, and propertiesof a light-emitting element 1 (a light-emitting element of oneembodiment of the present invention) in which 1,6chBnfAPrn (StructuralFormula (100)) described in Example 1 is used in a light-emitting layerand a comparative light-emitting element 2 in which a comparativeorganic compound 1,6BnfAPrn-03 (Structural Formula (200)) is used in alight-emitting layer will be described. Note that FIG. 17 illustratesthe element structure of the light-emitting elements used in thisexample, and Table 1 shows specific structures. Chemical formulae ofmaterials used in this example are shown below.

TABLE 1 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode Light-emitting ITSO PCPPn:MoOx PCPPn * 2mDBTBPDBq-IINBphen LiF Al element 1 (70 nm) (4:2, 10 nm) (25 nm) (15 nm) (10 nm) (1nm) (200 nm) Comparative ITSO PCPPn:MoOx PCPPn ** 2mDBTBPDBq-II NBphenLiF Al light-emitting (70 nm) (4:2, 10 nm) (25 nm) (15 nm) (10 nm) (1nm) (200 nm) element 2 *cgDBCzPA:1,6chBnfAPrn (1:0.03, 25 nm)**cgDBCzPA:1,6BnfAPrn-03 (1:0.03, 25 nm)

<<Fabrication of Light-Emitting Elements>>

In each of the light-emitting elements described in this example, asillustrated in FIG. 17 , a hole-injection layer 911, a hole-transportlayer 912, a light-emitting layer 913, an electron-transport layer 914,and an electron-injection layer 915 were stacked in this order over afirst electrode 901 formed over a substrate 900, and a second electrode903 was stacked over the electron-injection layer 915.

First, the first electrode 901 was formed over the substrate 900. Theelectrode area was set to 4 mm² (2 mm×2 mm). A glass substrate was usedas the substrate 900. The first electrode 901 was formed to a thicknessof 70 nm using indium tin oxide containing silicon oxide (ITSO) by asputtering method.

As pretreatment, a surface of the substrate was washed with water,baking was performed at 200° C. for 1 hour, and then UV ozone treatmentwas performed for 370 seconds. After that, the substrate was transferredinto a vacuum evaporation apparatus where the pressure had been reducedto approximately 10⁻⁴ Pa, and was subjected to vacuum baking at 170° C.for 60 minutes in a heating chamber of the vacuum evaporation apparatus,and then the substrate was cooled down for approximately 30 minutes.

Next, the hole-injection layer 911 was formed over the first electrode901. After the pressure in the vacuum evaporation apparatus was reducedto 10⁻⁴ Pa, the hole-injection layer 911 was formed by co-evaporation tohave a mass ratio of 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole(abbreviation: PCPPn) to molybdenum oxide of 4:2 and a thickness of 10nm.

Then, the hole-transport layer 912 was formed over the hole-injectionlayer 911. The hole-transport layer 912 was formed to a thickness of 25nm by evaporation of PCPPn.

Next, the light-emitting layer 913 was formed over the hole-transportlayer 912.

The light-emitting layer 913 in the light-emitting element 1 was formedby co-evaporation using7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA) as a host material and usingN,N′-(pyrene-1,6-diyl)bis(N-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6chBnfAPrn) as a guest material to have a weight ratioof cgDBCzPA to 1,6chBnfAPrn of 1:0.03. The thickness was set to 25 nm.

The light-emitting layer 913 in the comparative light-emitting element 2was formed by co-evaporation using cgDBCzPA as a host material and usingN,N′-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 1,6BnfAPrn-03) as a guest material to have a weight ratioof cgDBCzPA to 1,6BnfAPrn-03 of 1:0.03. The thickness was set to 25 nm.

Next, the electron-transport layer 914 was formed over thelight-emitting layer 913. The electron-transport layer 914 was formed inthe following manner:2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II) and2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation:NBphen) were sequentially deposited by evaporation to thicknesses of 15nm and 10 nm, respectively.

Then, the electron-injection layer 915 was formed over theelectron-transport layer 914. The electron-injection layer 915 wasformed to a thickness of 1 nm by evaporation of lithium fluoride (LiF).

After that, the second electrode 903 was formed over theelectron-injection layer 915. The second electrode 903 was formed usingaluminum to a thickness of 200 nm by an evaporation method. In thisexample, the second electrode 903 functioned as a cathode.

Through the above steps, the light-emitting elements in each of whichthe EL layer was provided between a pair of electrodes were eachfabricated over the substrate 900. The hole-injection layer 911, thehole-transport layer 912, the light-emitting layer 913, theelectron-transport layer 914, and the electron-injection layer 915described above were functional layers forming the EL layer in oneembodiment of the present invention. Furthermore, in all the evaporationsteps in the above fabrication method, evaporation was performed by aresistance-heating method.

Each of the light-emitting elements fabricated as described above wassealed using another substrate (not illustrated) in the followingmanner. In a glove box containing a nitrogen atmosphere, a sealant wasapplied so as to surround the light-emitting element formed over thesubstrate 900, the substrate (not illustrated) provided with a desiccantwas made to overlap with a desired position over the substrate 900, andthen irradiation with 365 nm ultraviolet light at 6 J/cm² was performed.

<<Operation Characteristics of Light-Emitting Elements>>

Operation characteristics of the fabricated light-emitting element 1 andcomparative light-emitting element 2 were measured. The measurement wasperformed at room temperature (in an atmosphere kept at 25° C.). FIGS.18 to 21 show the operation characteristics of the fabricatedlight-emitting element 1 and comparative light-emitting element 2.

Table 2 shows initial values of main characteristics of thelight-emitting element 1 and comparative light-emitting element 2 at aluminance of approximately 1000 cd/m².

TABLE 2 Current External density Current Power quantum Voltage Current(mA/ Chromaticity Luminance efficiency efficiency efficiency (V) (mA)cm²) (x, y) (cd/m²) (cd/A) (lm/W) %) Light-emitting 3.3 0.49 12 (0.14,0.09) 1100 9.3 8.8 11 element 1 Comparative 3.2 0.32 8.0 (0.14, 0.11)840 10 10 11 light-emitting element 2

The above results revealed that the light-emitting elements fabricatedin this example had a high current efficiency and a high externalquantum efficiency, and especially the light-emitting element 1 hadfavorable chromaticity.

FIG. 22 shows emission spectra when current at a current density of 12.5mA/cm² was applied to the light-emitting element 1 and comparativelight-emitting element 2. As shown in FIG. 22 , the emission spectra ofthe light-emitting element 1 and comparative light-emitting element 2have peaks at around 456 nm, which suggests that the peaks were derivedfrom light emission of 1,6BnfAPrn-03 and 1,6chBnfAPrn contained in thelight-emitting layers 913 of the light-emitting elements. At the sametime, comparison of the spectrum shapes shows that the spectrum of thelight-emitting element 1 has fewer spectral components on the longwavelength side than the spectrum of the comparative light-emittingelement 2. This led to the favorable blue chromaticity of thelight-emitting element 1.

Next, reliability tests were performed on the light-emitting element 1and the comparative light-emitting element 2. Results of the reliabilitytests are shown in FIG. 23 . In FIG. 23 , the vertical axis representsnormalized luminance (%) with an initial luminance of 100% and thehorizontal axis represents driving time (h) of the element. As thereliability tests, driving tests at a constant current of 2 mA wereperformed.

The results of the reliability tests showed that the light-emittingelement 1 of one embodiment of the present invention had higherreliability than the comparative light-emitting element 2. Specifically,when the time (LT₉₅) it took for the luminance to decay to 95% of theinitial luminance was compared, the LT₉₅ of the light-emitting element 1was 52 hours and that of the comparative light-emitting element 2 was 33hours, meaning that the lifetime of the light-emitting element 1 wasapproximately 1.6 times as long as that of the comparativelight-emitting element 2. The above suggests that the use of1,6chBnfAPrn (Structural Formula (100)), which is the organic compoundof one embodiment of the present invention, is effective in increasingthe lifetime of a light-emitting element.

Example 5 Synthesis Example 4

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis(N-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6nPrBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (118) in Embodiment 1, is described. The structure of1,6nPrBnfAPrn is shown below.

Step 1: Synthesis of 6-normalpropylbenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask were put 1.0 g (5.4 mmol) of3-normalpropyl-2-naphthol, 1.8 g (10 mmol) of 2-bromofluorobenzene, and3.5 g (11 mmol) of cesium carbonate, and the air in the flask wasreplaced with nitrogen. Then, 30 mL of N-methyl-2-pyrrolidone(abbreviation: NMP) was added and the resulting solution was degassedunder reduced pressure and then stirred for 6.5 hours at 170° C. under anitrogen stream. After the stirring, 3.5 g (11 mmol) of cesium carbonateand 0.28 g (1.1 mmol) of triphenylphosphine were added to this mixture.The resulting mixture was degassed by being stirred under reducedpressure. To this mixture was added 0.12 g (0.54 mmol) of palladium(II)acetate, and the resulting mixture was stirred for 11 hours at 170° C.under a nitrogen stream.

After the stirring, water was added to this mixture, and an aqueouslayer was subjected to extraction using ethyl acetate. The obtainedsolution of the extract and an organic layer were combined, and themixture was washed with water and saturated brine. Then, the mixture wasdried with magnesium sulfate. The mixture was separated by gravityfiltration, and the obtained filtrate was concentrated to give a brownoily substance. The obtained oily substance was purified by silica gelcolumn chromatography (a developing solvent: hexane) to give 1.1 g of atarget white solid in a yield of 75%. A synthesis scheme of Step 1 isshown in (c-1).

Results of nuclear magnetic resonance (1H NMR) spectroscopy measurementof the white solid obtained in Step 1 are shown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.61 (d, J=8.3 Hz, 1H), 8.42-8.39 (m, 1H),7.99 (d, J=8.3 Hz, 1H), 7.73-7.63 (m, 3H), 7.55-7.46 (m, 3H), 3.13 (t,J=6.8 Hz, 2H), 1.99-1.87 (m, J=7.8 Hz, 2H), 1.09 (t, J=7.3 Hz, 3H).

Step 2: Synthesis of 6-normalpropyl-8-iodobenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask was put 0.7 g (2.8 mmol) of6-normalpropylbenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 15 mL of tetrahydrofuran was added, andthe mixture was stirred at −80° C. Into this solution was dropped 3.0 mL(4.7 mmol) of n-butyllithium (a 1.6 mol/L n-hexane solution), thetemperature was returned to room temperature, and the mixture wasstirred for 2 hours under a nitrogen stream. After the stirring, thetemperature of the resulting mixture was reduced to −80° C.; then, asolution of 1.5 g (5.9 mmol) of iodine in 6 mL of tetrahydrofuran wasadded to the mixture, and stirring was performed for 15 hours while thetemperature was gradually returned to room temperature.

After the stirring, an aqueous solution of sodium thiosulfate was addedto this mixture, and an aqueous layer was subjected to extraction usingethyl acetate. The obtained solution of the extract and an organic layerwere combined, and the mixture was washed with water and saturatedbrine. Then, the mixture was dried with magnesium sulfate. The mixturewas separated by gravity filtration, and the obtained filtrate wasconcentrated to give a brown oily substance.

The obtained compound was purified by silica gel column chromatography(a developing solvent: hexane) to give 0.7 g of a target white solid ina yield of 65%. A synthesis scheme of Step 2 is shown in (c-2).

Results of ¹H NMR measurement of the white solid obtained in Step 2 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.55 (d, J=8.3 Hz, 1H), 8.36-8.33 (m, 1H),7.99 (d, J=8.3 Hz, 1H), 7.86-7.83 (m, 1H), 7.74 (s, 1H), 7.69-7.64 (m,1H), 7.56-7.51 (m, 1H), 7.25 (t, J=7.8 Hz, 1H), 3.17 (t, J=6.8 Hz, 2H),2.03-1.91 (m, J=7.8 Hz, 2H), 1.10 (t, J=7.3 Hz, 3H).

Step 3: Synthesis ofN-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine

Into a 200 mL three-neck flask were put 0.70 g (1.8 mmol) of6-normalpropyl-8-iodobenzo[b]naphtho[1,2-d]furan, 0.20 g (2.2 mmol) ofaniline, and 0.40 g (4.2 mmol) of sodium t-butoxide, and the air in theflask was replaced with nitrogen. To this mixture was added 10 mL oftoluene, and the resulting mixture was degassed under reduced pressure.To this mixture were added 0.30 mL (0.35 mmol) oftri(tert-butyl)phosphine (a 10 wt % hexane solution) and 40 mg (70 μmol)of bis(dibenzylideneacetone)palladium(0) and then, stirring wasperformed for 3 hours at 110° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown solid.

This solid was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give0.31 g of a target white solid in a yield of 50%. A synthesis scheme ofStep 3 is shown in (c-3).

Results of ¹H NMR measurement of the white solid obtained in Step 3 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.60 (d, J=8.3 Hz, 1H), 7.98-7.92 (m, 2H),7.71 (s, 1H), 7.69-7.63 (m, 1H), 7.55-7.50 (m, 1H), 7.41-7.27 (m, 6H),7.05-7.01 (m, 1H), 6.28 (brs, 1H), 3.13 (t, J=6.8 Hz, 2H), 1.98-1.86 (m,J=7.8 Hz, 2H), 1.08 (t, J=7.3 Hz, 3H).

Step 4: Synthesis of 1,6nPrBnfAPrn

Into a 50 mL three-neck flask were put 0.16 g (0.44 mmol) of1,6-dibromopyrene, 0.31 g (0.88 mmol) ofN-phenyl-6-normalpropylbenzo[b]naphtho[1,2-d]furan-8-amine, 0.17 g (1.8mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 5 mL of mesitylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 6 hours at 170° C. under a nitrogenstream.

After the stirring, 30 mL of toluene was added, heating was performed,and the resulting mixture was purified by silica gel columnchromatography (a developing solvent: toluene) to give a target yellowsolid. The obtained yellow solid was recrystallized with toluene to give0.23 g of a target yellow solid in a yield of 58%. A synthesis scheme ofStep 4 is shown in (c-4).

By a train sublimation method, 0.23 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 300° C. under a pressure of 3.3 Pa for 15 hours.After the purification by sublimation, 0.19 g of a target yellow solidwas obtained at a collection rate of 83%.

Results of ¹H NMR measurement of the yellow solid obtained in Step 4 areshown below. Furthermore, ¹H NMR charts are shown in FIGS. 24A to 24C.Note that FIG. 24B is an enlarged chart showing the range of 6.5 ppm to9.0 ppm in FIG. 24A. FIG. 24C is an enlarged chart showing the range of0 ppm to 3.5 ppm in FIG. 24A. The results reveal that 1,6nPrBnfAPrn(Structural Formula (118)) was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.57 (d, J=8.8 Hz, 2H), 8.32 (d, J=9.3 Hz,2H), 8.12-8.04 (m, 4H), 7.92-7.85 (m, 6H), 7.64-7.59 (m, 2H), 7.50-7.45(m, 4H), 7.34-7.30 (m, 4H), 7.23-7.17 (m, 4H), 7.01-6.95 (m, 6H),2.42-2.37 (m, 4H), 1.16-1.08 (m, 4H), 0.44 (t, J=7.3 Hz, 6H).

Results of measurement of absorption spectra and emission spectra of atoluene solution and a solid thin film of 1,6nPrBnfAPrn are describedbelow. The measurement method was similar to that described in Example1.

FIG. 25A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 25B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 25A, the toluene solution of1,6nPrBnfAPrn exhibited an absorption peak at around 423 nm and anemission wavelength peak at 451 nm (excitation wavelength: 408 nm).Furthermore, as shown by the results in FIG. 25B, the solid thin film of1,6nPrBnfAPrn exhibited an absorption peak at around 428 nm and emissionwavelength peaks at around 461 nm and 489 nm (excitation wavelength: 410nm).

Example 6 Synthesis Example 5

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis(N-phenyl-6-tert-butylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6tBuBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (117) in Embodiment 1, is described. The structure of1,6tBuBnfAPrn is shown below.

Step 1: Synthesis of 6-tert-butylbenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask were put 1.0 g (5.0 mmol) of3-tert-butyl-2-naphthol, 1.8 g (10 mmol) of 2-bromofluorobenzene, and3.4 g (10 mmol) of cesium carbonate, and the air in the flask wasreplaced with nitrogen. Then, 30 mL of N-methyl-2-pyrrolidone(abbreviation: NMP) was added and the resulting mixture was degassedunder reduced pressure and then stirred for 6.5 hours at 170° C. under anitrogen stream. After the stirring, 3.4 g (10 mmol) of cesium carbonateand 0.14 g (0.53 mmol) of triphenylphosphine were added to this mixture.The resulting mixture was degassed by being stirred under reducedpressure. To this mixture was added 60 mg (0.27 mmol) of palladium(II)acetate, and the resulting mixture was stirred for 4.5 hours at 170° C.under a nitrogen stream.

After the stirring, water was added to this mixture, and an aqueouslayer was subjected to extraction using ethyl acetate. The obtainedsolution of the extract and an organic layer were combined, and themixture was washed with water and saturated brine. Then, the mixture wasdried with magnesium sulfate. The mixture was separated by gravityfiltration, and the obtained filtrate was concentrated to give a brownoily substance. The obtained oily substance was purified by silica gelcolumn chromatography (a developing solvent: hexane) to give 1.2 g of atarget white solid in a yield of 90%. A synthesis scheme of Step 1 isshown in (d-1).

Results of ¹H NMR measurement of the white solid obtained in Step 1 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.62 (d, J=8.3 Hz, 1H), 8.43-8.40 (m, 1H),8.01-7.98 (m, 1H), 7.79 (s, 1H), 7.75-7.64 (m, 2H), 7.55-7.46 (m, 3H),1.66 (s, 9H).

Step 2: Synthesis of 6-tert-butyl-8-iodobenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask was put 1.2 g (4.5 mmol) of6-tert-butylbenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 35 mL of tetrahydrofuran was added, andthe mixture was stirred at −80° C. Into this solution was dropped 4.0 mL(6.2 mmol) of n-butyllithium (a 1.6 mol/L n-hexane solution), thetemperature was returned to room temperature, and the mixture wasstirred for 2 hours under a nitrogen stream. After the stirring, thetemperature of the resulting mixture was reduced to −80° C.; then, asolution of 2.3 g (9.0 mmol) of iodine in 15 mL of tetrahydrofuran wasadded to the mixture, and stirring was performed for 15 hours while thetemperature was gradually returned to room temperature.

After the stirring, an aqueous solution of sodium thiosulfate was addedto this mixture, and an aqueous layer was subjected to extraction usingethyl acetate. The obtained solution of the extract and an organic layerwere combined, and the mixture was washed with water and saturatedbrine. Then, the mixture was dried with magnesium sulfate. The mixturewas separated by gravity filtration, and the obtained filtrate wasconcentrated to give a brown oily substance.

The obtained compound was purified by silica gel column chromatography(a developing solvent: hexane) to give 1.2 g of a target white solidwith an NMR purity of 45% in a yield of 35%. A synthesis scheme of Step2 is shown in (d-2).

Results of ¹H NMR measurement of the white solid obtained in Step 2 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.55 (d, J=8.3 Hz, 1H), 8.37-8.34 (m, 1H),8.01-7.98 (m, 1H), 7.86-7.78 (m, 2H), 7.70-7.64 (m, 1H), 7.56-7.51 (m,1H), 7.25-7.20 (m, 1H), 1.70 (s, 9H).

Step 3: Synthesis ofN-phenyl-6-tert-butylbenzo[b]naphtho[1,2-d]furan-8-amine

Into a 200 mL three-neck flask were put 1.2 g (2.9 mmol) of6-tert-butyl-8-iodobenzo[b]naphtho[1,2-d]furan, 0.33 g (3.5 mmol) ofaniline, and 0.68 g (7.1 mmol) of sodium t-butoxide, and the air in theflask was replaced with nitrogen. To this mixture was added 15 mL oftoluene, and the resulting mixture was degassed under reduced pressure.To this mixture were added 0.30 mL (0.35 mmol) oftri(tert-butyl)phosphine (a 10 wt % hexane solution) and 40 mg (70 μmol)of bis(dibenzylideneacetone)palladium(0) and then, stirring wasperformed for 3 hours at 90° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown solid.

This solid was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give0.48 g of a target white solid in a yield of 82%. A synthesis scheme ofStep 3 is shown in (d-3).

Results of ¹H NMR measurement of the white solid obtained in Step 3 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.61 (d, J=8.3 Hz, 1H), 8.01-7.95 (m, 2H),7.78 (s, 1H), 7.70-7.64 (m, 1H), 7.56-7.50 (m, 1H), 7.41-7.28 (m, 6H),7.06-7.00 (m, 1H), 6.19 (brs, 1H), 3.13 (s, 9H).

Step 4: Synthesis of 1,6tBuBnfAPrn

Into a 200 mL three-neck flask were put 0.23 g (0.64 mmol) of1,6-dibromopyrene, 0.48 g (1.3 mmol) ofN-phenyl-6-tert-butylbenzo[b]naphtho[1,2-d]furan-8-amine, 0.25 g (2.6mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 10 mL of mesitylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 7 hours at 170° C. under a nitrogenstream.

After the stirring, 30 mL of toluene was added, heating was performed,and the resulting mixture was purified by silica gel columnchromatography (a developing solvent was a mixed solvent of hexane andtoluene, and the ratio of hexane to toluene was changed from 9:1 to 7:3to form a gradient) to give a target yellow solid. The obtained yellowsolid was recrystallized with toluene to give 0.24 g of a target yellowsolid in a yield of 40%. A synthesis scheme of Step 4 is shown in (d-4).

By a train sublimation method, 0.21 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 330° C. under a pressure of 1.8×10⁻² Pa for 8 hours.After the purification by sublimation, 0.17 g of a target yellow solidwas obtained at a collection rate of 81%.

Results of ¹H NMR measurement of the yellow solid obtained in Step 4 areshown below. Furthermore, ¹H NMR charts are shown in FIGS. 26A to 26C.Note that FIG. 26B is an enlarged chart showing the range of 6.5 ppm to9.0 ppm in FIG. 26A. FIG. 26C is an enlarged chart showing the range of0.5 ppm to 3.0 ppm in FIG. 26A. The results reveal that 1,6tBuBnfAPrn(Structural Formula (117)) was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.59 (d, J=8.8 Hz, 2H), 8.27 (d, J=9.3 Hz,2H), 8.15 (d, J=7.8 Hz, 2H), 8.04 (d, J=8.3 Hz, 2H), 7.94-7.82 (m, 6H),7.66-7.61 (m, 4H), 7.51-7.46 (m, 2H), 7.35-7.29 (m, 2H), 7.22-7.16 (m,6H), 7.01-6.91 (m, 6H), 1.02 (s, 18H).

Results of measurement of absorption spectra and emission spectra of atoluene solution and a solid thin film of 1,6tBuBnfAPrn are describedbelow. The measurement method was similar to that described in Example1.

FIG. 27A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 27B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 27A, the toluene solution of1,6tBuBnfAPrn exhibited an absorption peak at around 424 nm and anemission wavelength peak at 450 nm (excitation wavelength: 410 nm).Furthermore, as shown by the results in FIG. 27B, the solid thin film of1,6tBuBnfAPrn exhibited an absorption peak at around 426 nm and emissionwavelength peaks at around 460 nm and 495 nm (excitation wavelength: 410nm).

Example 7 Synthesis Example 6

In this example, a method for synthesizingN,N′-bis(pyrene-1,6-diyl)bis(N-phenyl-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: 1,6TMSBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (145) in Embodiment 1, is described. The structure of1,6TMSBnfAPrn is shown below.

Step 1: Synthesis of8-chloro-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan

Into a 100 mL three-neck flask was put 1.1 g (4.4 mmol) of8-chlorobenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 20 mL of tetrahydrofuran was added, andthe mixture was stirred at −80° C. Into this solution was dropped 4.0 mL(6.2 mmol) of n-butyllithium (a 1.6 mol/L n-hexane solution), thetemperature was returned to room temperature, and the mixture wasstirred for 2 hours under a nitrogen stream. After the stirring, thetemperature of the resulting mixture was reduced to −80° C.; then, asolution of 1.1 mL (8.7 mmol) of chlorotrimethylsilane in 10 mL oftetrahydrofuran was added to the mixture, and stirring was performed for15 hours while the temperature was gradually returned to roomtemperature.

After the stirring, an aqueous solution of sodium hydrogencarbonate wasadded to this mixture, and an aqueous layer was subjected to extractionusing toluene. The obtained solution of the extract and an organic layerwere combined, and the mixture was washed with water and saturatedbrine. Then, the mixture was dried with magnesium sulfate. The mixturewas separated by gravity filtration, and the obtained filtrate wasconcentrated to give a brown oily substance.

The obtained compound was purified by silica gel column chromatography(a developing solvent: hexane) to give 0.67 g of a target white solid ina yield of 47%. A synthesis scheme of Step 1 is shown in (e-1).

Results of ¹H NMR measurement of the white solid obtained in Step 1 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.57 (d, J=8.3 Hz, 1H), 8.29-8.26 (m, 1H),8.05-8.02 (m, 2H), 7.75-7.69 (m, 1H), 7.58-7.44 (m, 2H), 7.41 (t, J=7.8Hz, 1H), 0.55 (s, 9H).

Step 2: Synthesis ofN-phenyl-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan-8-amine

Into a 200 mL three-neck flask were put 0.65 g (2.0 mmol) of8-chloro-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan, 0.23 g (2.5 mmol)of aniline, and 0.50 g (5.2 mmol) of sodium t-butoxide, and the air inthe flask was replaced with nitrogen. To this mixture was added 15 mL oftoluene, and the resulting mixture was degassed under reduced pressure.To this mixture were added 0.30 mL (0.35 mmol) of tri-tert-butylphosphine (a 10 wt % hexane solution), 0.52 g (1.5 mmol) ofn-butyl-diadamantylphosphine, and 0.16 g (0.28 mmol) ofbis(dibenzylideneacetone)palladium(0) and then, stirring was performedfor 18 hours at 120° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown oily substance.

This oily substance was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give0.45 g of a target white solid in a yield of 59%. A synthesis scheme ofStep 2 is shown in (e-2).

Results of ¹H NMR measurement of the white solid obtained in Step 2 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.62 (d, J=8.3 Hz, 1H), 8.04-7.94 (m, 3H),7.74-7.69 (m, 1H), 7.57-7.51 (m, 1H), 7.40-7.32 (m, 4H), 7.27-7.23 (m,2H), 7.05-6.99 (m, 1H), 6.14 (brs, 1H), 0.49 (s, 9H).

Step 3: Synthesis of 1,6TMSBnfAPrn

Into a 200 mL three-neck flask were put 0.21 g (0.58 mmol) of1,6-dibromopyrene, 0.45 g (0.88 mmol) ofN-phenyl-6-trimethylsilylbenzo[b]naphtho[1,2-d]furan-8-amine, 0.23 g(1.8 mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 5 mL of mesitylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 4 hours at 170° C. under a nitrogenstream.

After the stirring, 500 mL of toluene was added and heating wasperformed; then, hot filtration was performed through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina. A yellow solid obtained by concentration of the resultingfiltrate was purified by silica gel column chromatography (a developingsolvent was a mixed solvent of hexane and toluene, and the ratio ofhexane to toluene was changed from 9:1 to 7:3 to form a gradient) togive a target yellow solid. The obtained yellow solid was recrystallizedwith toluene to give 0.30 g of a target yellow solid in a yield of 54%.

By a train sublimation method, 0.30 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 340° C. under a pressure of 2.0×10⁻² Pa for 8 hours.After the purification by sublimation, 0.22 g of a target yellow solidwas obtained at a collection rate of 74%. A synthesis scheme of Step 3is shown in (e-3).

Results of ¹H NMR measurement of the yellow solid obtained in Step 3 areshown below. Furthermore, ¹H NMR charts are shown in FIGS. 28A to 28C.Note that FIG. 28B is an enlarged chart showing the range of 6.5 ppm to9.0 ppm in FIG. 28A. FIG. 28C is an enlarged chart showing the range of−0.5 ppm to 2.0 ppm in FIG. 28A. The results reveal that 1,6TMSBnfAPrn(Structural Formula (145)) was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.62 (d, J=8.8 Hz, 2H), 8.26 (d, J=9.3 Hz,2H), 8.16-8.13 (m, 2H), 8.05-7.98 (m, 4H), 7.91-7.82 (m, 6H), 7.72-7.67(m, 2H), 7.54-7.48 (m, 2H), 7.31-7.26 (m, 2H), 7.18-7.11 (m, 6H),6.94-6.89 (m, 6H), 0.04 (s, 18H).

Results of measurement of absorption spectra and emission spectra of atoluene solution and a solid thin film of 1,6TMSBnfAPrn are describedbelow. The measurement method was similar to that described in Example1.

FIG. 29A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 29B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 29A, the toluene solution of1,6TMSBnfAPrn exhibited an absorption peak at around 422 nm and anemission wavelength peak at 451 nm (excitation wavelength: 415 nm).Furthermore, as shown by the results in FIG. 29B, the solid thin film of1,6TMSBnfAPrn exhibited an absorption peak at around 428 nm and emissionwavelength peaks at around 460 nm and 485 nm (excitation wavelength: 400nm).

Example 8 Synthesis Example 7

In this example, a method for synthesizingN,N′-(3,8-dicyclohexylpyrene-1,6-diyl)bis[N-phenyl-(6-cyclohexylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: ch-1,6chBnfAPrn), which is the organic compound of oneembodiment of the present invention and which is represented byStructural Formula (142) in Embodiment 1, is described. The structure ofch-1,6chBnfAPrn is shown below.

Step 1: Synthesis of ch-1,6chBnfAPrn

Into a 200 mL three-neck flask were put 1.5 g (2.9 mmol) of1,6-dibromo-3,8-dicyclohexylpyrene, 2.3 g (5.8 mmol) ofN-phenyl-6-cyclohexylbenzo[b]naphtho[1,2-d]furan-8-amine, 1.1 g (11mmol) of sodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 30 mL of mesitylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 5.5 hours at 170° C. under a nitrogenstream.

After the stirring, 2.5 L of toluene was added and heating wasperformed; then, hot filtration was performed through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina.

A yellow solid obtained by concentration of the resulting filtrate waspurified by silica gel column chromatography (a developing solvent:toluene) to give a target yellow solid. The obtained yellow solid wasrecrystallized with toluene to give 2.2 g of a target yellow solid in ayield of 67%.

By a train sublimation method, 1.3 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 360° C. under a pressure of 2.9×10⁻² Pa for 15hours. After the purification by sublimation, 1.0 g of a target yellowsolid was obtained at a collection rate of 77%. A synthesis scheme ofStep 1 is shown in (f-1).

Results of ¹H NMR measurement of the yellow solid obtained in Step 1 areshown below. Furthermore, ¹H NMR charts are shown in FIGS. 30A to 30C.Note that FIG. 30B is an enlarged chart showing the range of 6.5 ppm to9.0 ppm in FIG. 30A. FIG. 30C is an enlarged chart showing the range of1.0 ppm to 4.0 ppm in FIG. 30A. The results reveal that ch-1,6chBnfAPrn(Structural Formula (142)) was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.59 (d, J=8.3 Hz, 2H), 8.30 (d, J=9.8 Hz,2H), 8.15-8.09 (m, 4H), 7.92 (d, J=7.8 Hz, 2H), 7.81 (s, 2H), 7.65-7.60(m, 2H), 7.56 (s, 2H), 7.50-7.45 (m, 2H), 7.33-7.28 (m, 2H), 7.21-7.14(m, 6H), 6.99-6.92 (m, 6H), 3.46 (m, 2H), 2.54 (m, 2H), 1.92-0.80 (m,40H).

Results of measurement of absorption spectra and emission spectra of atoluene solution and a solid thin film of ch-1,6chBnfAPrn are describedbelow. The measurement method was similar to that described in Example1.

FIG. 31A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 31B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 31A, the toluene solution ofch-1,6chBnfAPrn exhibited an absorption peak at around 425 nm and anemission wavelength peak at 452 nm (excitation wavelength: 410 nm).Furthermore, as shown by the results in FIG. 31B, the solid thin film ofch-1,6chBnfAPrn exhibited an absorption peak at around 427 nm andemission wavelength peaks at around 460 nm and 505 nm (excitationwavelength: 400 nm).

Example 9 Synthesis Example 8

In this example, a method for synthesizing an organic compoundN,N′-(3,8-dicyclohexylpyrene-1,6-diyl)bis(N-phenylbenzo[b]naphtho[1,2-d]furan-8-amine)(abbreviation: ch-1,6BnfAPrn-02) is described. The structure ofch-1,6BnfAPrn-02 is shown below.

Step 1: Synthesis of 1,6-dicyclohexylpyrene

Into a 200 mL three-neck flask were put 2.0 g (5.6 mmol) of1,6-dibromopyrene and 90 mg (0.19 mmol) of2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (abbreviation:XPhos), and the air in the flask was replaced with nitrogen. Then, 30 mLof tetrahydrofuran (abbreviation: THF) was added, and the resultingmixture was degassed under reduced pressure and then stirred at 70° C.To this mixture was added 80 mg (87 μmol) oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and24 mL of cyclohexylmagnesium bromide (a 1.0 mol/L tetrahydrofuransolution, 24 mmol) was dropped into the mixture; then, the resultingmixture was stirred for 6.5 hours at 70° C. under a nitrogen stream.

After the stirring, this mixture was dropped into 0° C. hydrochloricacid (1 mol/L), and an aqueous layer of the resulting mixture wassubjected to extraction using toluene. The obtained solution of theextract and an organic layer were combined, and the mixture was washedwith water and saturated brine. Then, the mixture was dried withmagnesium sulfate. The mixture was separated by gravity filtration, andthe obtained filtrate was concentrated to give a yellow oily substance.

The obtained oily substance was purified by silica gel columnchromatography (a developing solvent: hexane) to give 1.47 g of ayellowish white solid. This solid was purified by recrystallization, sothat 0.85 g of a target white solid was obtained in a yield of 42%. Asynthesis scheme of Step 1 is shown in (g-1).

Results of ¹H NMR measurement of the white solid obtained in Step 1 areshown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.32 (d, J=9.3 Hz, 2H), 8.14 (d, J=8.3 Hz,2H), 8.06 (d, J=9.3 Hz, 2H), 7.96 (d, J=7.8 Hz, 2H), 3.67-3.60 (m, 2H),2.13-1.39 (m, 20H).

Step 2: Synthesis of 1,6-dibromo-3,8-dicyclohexylpyrene

Into a 300 mL three-neck flask was put 5.1 g (14 mmol) of1,6-dicyclohexylpyrene, and the air in the flask was replaced withnitrogen. Then, 80 mL of N,N-dimethylformamide (abbreviation: DMF) wasadded and stirring was performed at 110° C. To the resulting mixture wasadded 7.7 g (43 mmol) of N-bromosuccinimide (abbreviation: NBS), andstirring was performed for 23 hours at 80° C.

After the stirring, water was added to this mixture and a precipitatedsolid was separated by suction filtration. The obtained brownish whitesolid was washed with methanol and recrystallized with toluene to give3.1 g of a target brownish white solid in a yield of 76%. A synthesisscheme of Step 2 is shown in (g-2).

Results of ¹H NMR measurement of the brownish white solid obtained inStep 2 are shown below.

¹H NMR (CDCl₃, 300 MHz): σ=8.47 (d, J=9.8 Hz, 2H), 8.36 (d, J=9.3 Hz,2H), 8.20 (s, 2H), 3.64-3.56 (m, 2H), 2.12-1.57 (m, 20H).

Step 3: Synthesis of N-phenyl-benzo[b]naphtho[1,2-d]furan-8-amine

Into a 200 mL three-neck flask were put 1.1 g (4.4 mmol) of8-chlorobenzo[b]naphtho[1,2-d]furan, 0.49 g (5.3 mmol) of aniline, and1.0 g (10 mmol) of sodium t-butoxide, and the air in the flask wasreplaced with nitrogen. To this mixture was added 25 mL of toluene, andthe resulting mixture was degassed under reduced pressure. To thismixture were added 0.26 g (0.72 mmol) of n-butyl-diadamantylphosphineand 80 mg (0.14 mmol) of bis(dibenzylideneacetone)palladium(0) and then,stirring was performed for 10 hours at 120° C. under a nitrogen stream.

After the stirring, 300 mL of toluene was added to the resulting mixtureand then, suction filtration was performed through Florisil (Catalog No.066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The obtained filtrate was concentratedto give a brown oily substance.

This oily substance was purified by silica gel column chromatography (adeveloping solvent was a mixed solvent of hexane:toluene=4:1) to give0.76 g of a target white solid in a yield of 57%. A synthesis scheme ofStep 3 is shown in (g-3).

Step 4: Synthesis of ch-1,6BnfAPrn-02

Into a 200 mL three-neck flask were put 0.64 g (1.2 mmol) of1,6-dibromo-3,8-dicyclohexylpyrene, 0.76 g (2.5 mmol) ofN-phenyl-benzo[b]naphtho[1,2-d]furan-8-amine, 0.50 g (5.2 mmol) ofsodium t-butoxide, and 60 mg (0.15 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (abbreviation:SPhos), and the air in the flask was replaced with nitrogen. To thismixture was added 15 mL of mesitylene, and the resulting mixture wasdegassed under reduced pressure; then, 40 mg (70 μmol) ofbis(dibenzylideneacetone)palladium(0) was added to the mixture and theresulting mixture was stirred for 6 hours at 170° C. under a nitrogenstream.

After the stirring, 500 mL of toluene was added and heating wasperformed; then, hot filtration was performed through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.), Celite(Catalog No. 537-02305 produced by Wako Pure Chemical Industries, Ltd.),and alumina. A yellow solid obtained by concentration of the resultingfiltrate was purified by silica gel column chromatography to give atarget yellow solid. The obtained yellow solid was recrystallized withtoluene to give 0.95 g of a target yellow solid in a yield of 79 0.

By a train sublimation method, 0.95 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the yellowsolid was heated at 350° C. under a pressure of 2.3×10⁻² Pa for 7 hours.After the purification by sublimation, 0.65 g of a target yellow solidwas obtained at a collection rate of 68%. A synthesis scheme of Step 4is shown in (g-4).

Results of ¹H NMR measurement of the yellow solid obtained in Step 4 areshown below. Furthermore, H NMR charts are shown in FIGS. 32A to 32C.Note that FIG. 32B is an enlarged chart showing the range of 6.5 ppm to9.0 ppm in FIG. 32A. FIG. 32C is an enlarged chart showing the range of1.0 ppm to 4.0 ppm in FIG. 32A. The results reveal that ch-1,6BnfAPrn-02was obtained.

¹H NMR (CDCl₃, 300 MHz): σ=8.64-8.61 (m, 2H), 8.32 (d, J=9.3 Hz, 2H),8.16-8.12 (m, 4H), 8.01-7.96 (m, 4H), 7.87-7.84 (m, 2H), 7.73-7.68 (m,2H), 7.59-7.50 (m, 4H), 7.33-7.28 (m, 2H), 7.21-7.14 (m, 6H), 6.94-6.85(m, 6H), 3.49 (m, 2H), 2.01-1.28 (m, 20H).

Results of measurement of absorption spectra and emission spectra of asolid thin film and a toluene solution of ch-1,6BnfAPrn-02 are describedbelow. The measurement method was similar to that described in Example1.

FIG. 33A shows the obtained absorption and emission spectra of thetoluene solution. The horizontal axis represents wavelength and thevertical axes represent absorption intensity and emission intensity.FIG. 33B shows the obtained absorption and emission spectra of the solidthin film. The horizontal axis represents wavelength and the verticalaxes represent absorption intensity and emission intensity.

As shown by the results in FIG. 33A, the toluene solution ofch-1,6BnfAPrn-02 exhibited an absorption peak at around 420 nm and anemission wavelength peak at 453 nm (excitation wavelength: 415 nm).Furthermore, as shown by the results in FIG. 33B, the solid thin film ofch-1,6BnfAPrn-02 exhibited an absorption peak at around 423 nm andemission wavelength peaks at around 464 nm and 512 nm (excitationwavelength: 400 nm).

Example 10

In this example, the quantum yields of the organic compounds in Examples1 to 3 and 5 to 9 were measured. For the measurement, the toluenesolutions that were used for the measurement of the emission spectra inthese examples were used. The measurement was conducted with the use ofan absolute PL quantum yield measurement system (Quantaurus-QYC11347-01) manufactured by Hamamatsu Photonics K.K. The excitationwavelength was set in the range of 350 nm to 450 nm at intervals of 10nm, and the maximum among the quantum yields obtained in the measurementrange was regarded as the quantum yield of the organic compound.

Table 3 shows the measurement results. As Table 3 shows, thelight-emitting materials of embodiments of the present invention haveextremely high quantum yields and are thus suitable as light-emittingmaterials for light-emitting elements.

TABLE 3 Compound Quantum yield (%) Synthesis Example 1 1,6chBnfAPrn 82Synthesis Example 2 1,6oMechBnfAPrn 85 Synthesis Example 3 1,6iPrBnfAPrn72 Synthesis Example 4 1,6nPrBnfAPrn 86 Synthesis Example 51,6tBuBnfAPrn 86 Synthesis Example 6 1,6TMSBnfAPrn 84 Synthesis Example7 ch-1,6chBnfAPrn 94 Synthesis Example 8 ch-1,6BnfAPrn-02 94

Example 11

In this example, the HOMO levels and LUMO levels of the organiccompounds synthesized in Synthesis Examples 1 to 8 in Examples 1 to 3and 5 to 9 were calculated from cyclic voltammetry (CV) measurementresults. The method and results of the calculation are as follows.

An electrochemical analyzer (ALS model 600A or 600C, produced by BASInc.) was used for the measurement. To prepare a solution for the CVmeasurement, dehydrated dimethylformamide (DMF, manufactured bySigma-Aldrich Inc., 99.8%, catalog No. 22705-6) was used as a solvent,and tetra-n-butylammonium perchlorate (n-Bu₄NClO₄, manufactured by TokyoChemical Industry Co., Ltd., catalog No. T0836) as a supportingelectrolyte was dissolved at a concentration of 100 mmol/L. Further, theobject to be measured was dissolved at a concentration of 2 mmol/L.

A platinum electrode (PTE platinum electrode, produced by BAS Inc.) wasused as a working electrode, a platinum electrode (Pt counter electrodefor VC-3 (5 cm), produced by BAS Inc.) was used as an auxiliaryelectrode, and an Ag/Ag⁺ electrode (RE-7 reference electrode fornonaqueous solvent, produced by BAS Inc.) was used as a referenceelectrode. Note that the measurement was conducted at room temperature(20° C. to 25° C.).

In addition, the scan speed in the CV measurement was fixed to 0.1V/sec, and an oxidation potential Ea [V] and a reduction potential Ec[V] with respect to the reference electrode were measured. The potentialEa is an intermediate potential of an oxidation-reduction wave, and thepotential Ec is an intermediate potential of a reduction-oxidation wave.Here, since the potential energy of the reference electrode used in thisexample with respect to the vacuum level is known to be −4.94 [eV], theHOMO level and the LUMO level can be calculated by the followingformulae: HOMO level [eV]=−4.94−Ea and LUMO level [eV]=−4.94−Ec. Table 4shows the measurement results.

TABLE 4 Compound HOMO LUMO Synthesis Example 1 1,6chBnfAPrn −5.46 −2.66Synthesis Example 2 1,6oMechBnfAPrn −5.36 −2.60 Synthesis Example 31,6iPrBnfAPrn −5.47 −2.65 Synthesis Example 4 1,6nPrBnfAPrn −5.45 −2.65Synthesis Example 5 1,6tBuBnfAPrn −5.48 −2.66 Synthesis Example 61,6TMSBnfAPrn −5.44 −2.66 Synthesis Example 7 ch-1,6chBnfAPrn −5.40−2.60 Synthesis Example 8 ch-1,6BnfAPrn-02 −5.39 −2.62

From Table 4, it is found that the organic compounds of embodiments ofthe present invention have deeper HOMO levels than ch-1,6BnfAPrn-02,which is the organic compound synthesized as a reference in SynthesisExample 8. Unlike ch-1,6BnfAPrn-02, the organic compounds of embodimentsof the present invention each have an alkyl group in abenzo[b]naphtho[1,2-d]furan skeleton and this probably led to theirdeeper HOMO levels and accordingly wider band gaps (BG), enabling theirshorter-wavelength light emission. Note that the HOMO level of1,6oMechBnfAPrn (one embodiment of the present invention described inSynthesis Example 2) is shallower than the HOMO levels of the compoundsin the other synthesis examples probably because in 1,6oMechBnfAPrn, Ar¹of General Formula (G1) has a methyl group with an electron-donatingproperty.

Example 12

In this example, a light-emitting element 3 using 1,6TMSBnfAPrn(Structural Formula (145), Example 7) in its light-emitting layer, alight-emitting element 4 using 1,6nPrBnfAPrn (Structural Formula (118),Example 5) in its light-emitting layer, and a light-emitting element 5using 1,6tBuBnfAPrn (Structural Formula (117), Example 6) in itslight-emitting layer were fabricated as light-emitting elements ofembodiments of the present invention, and their characteristics weremeasured.

Element structures of the light-emitting elements used in this exampleare similar to the element structure described in Example 4 withreference to FIG. 17 , and Table 5 shows specific structures of layersin the element structures. Chemical formulae of materials used in thisexample are shown below.

TABLE 5 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode Light- ITSO PCPPn:MoOx PCPPn * cgDBCzPA NBphen LiF Alemitting (70 nm) (4:2, 10 nm) (30 nm) (15 nm) (10 nm) (1 nm) (200 nm)element 3 Light- ITSO PCPPn:MoOx PCPPn ** cgDBCzPA NBphen LiF Alemitting (70 nm) (4:2, 10 nm) (30 nm) (15 nm) (10 nm) (1 nm) (200 nm)element 4 Light- ITSO PCPPn:MoOx PCPPn *** cgDBCzPA NBphen LiF Alemitting (70 nm) (4:2, 10 nm) (30 nm) (15 nm) (10 nm) (1 nm) (200 nm)element 5 *cgDBCzPA:1,6TMSBnfAPr (1:0.03, 25 nm)**cgDBCzPA:1,6nPrBnfAPrn (1:0.03, 25 nm) ***cgDBCzPA:1,6tBuBnfAPrn(1:0.03, 25 nm)

<<Operation Characteristics of Light-Emitting Elements>>

Operation characteristics of the fabricated light-emitting elements 3 to5 were measured. The measurement was carried out at room temperature.The results are shown in FIGS. 34 to 37 .

Table 6 shows initial values of main characteristics of thelight-emitting elements at a luminance of approximately 1000 cd/m².

TABLE 6 Current External density Current Power quantum Voltage Current(mA/ Chromaticity Luminance efficiency efficiency efficiency (V) (mA)cm²) (x, y) (cd/m²) (cd/A) (lm/W) %) Light-emitting 3.2 0.45 11 (0.14,0.12) 1100 10 10 10 element 3 Light-emitting 3.2 0.42 11 (0.14, 0.11)1100 10 10 11 element 4 Light-emitting 3.1 0.32 8.1 (0.14, 0.11) 830 1010 11 element 5

The above results show that the light-emitting element 3, thelight-emitting element 4, and the light-emitting element 5 fabricated inthis example have an external quantum efficiency of 10% or higher andthat these light-emitting elements have high efficiencies and exhibitfavorable blue light emission.

FIG. 38 shows emission spectra when current at a current density of 12.5mA/cm² was applied to the light-emitting elements. As shown in FIG. 38 ,the emission spectra of the light-emitting elements have peaks at around475 nm to 458 nm, which suggests that the peaks were derived from lightemission of the light-emitting substances contained in thelight-emitting layers 913. In addition, the emission spectra have halfwidths of 40 nm to 45 nm to have extremely sharp shapes, which meansthat these light-emitting elements exhibit extremely deep bluechromaticities.

Example 13

In this example, a light-emitting element 6 using ch-1,6chBnfAPrn(Structural Formula (142), Example 8) in its light-emitting layer wasfabricated as a light-emitting element of one embodiment of the presentinvention and a comparative light-emitting element 7 usingch-1,6BnfAPrn-02 (Example 9) in its light-emitting layer was fabricatedas a reference, and their characteristics were measured.

Element structures of the light-emitting elements used in this exampleare similar to the element structure described in Example 4 withreference to FIG. 17 , and Table 7 shows specific structures of layersin the element structures. Chemical formulae of materials used in thisexample are shown below.

TABLE 7 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode Light-emitting ITSO PCPPn:MoOx PCPPn * cgDBCzPA NBphenLiF Al element 6 (70 nm) (4:2, 10 nm) (30 nm) (15 nm) (10 nm) (1 nm)(200 nm) Comparative ITSO PCPPn:MoOx PCPPn ** cgDBCzPA NBphen LiF Allight-emitting (70 nm) (4:2, 10 nm) (30 nm) (15 nm) (10 nm) (1 nm) (200nm) element 7 *cgDBCzPA:ch-1,6chBnfAPrn (1:0.03, 25 nm)**cgDBCzPA:ch-1,6BnfAPrn-02 (1:0.03, 25 nm)

<<<Operation Characteristics of Light-Emitting Elements>>

Operation characteristics of the fabricated light-emitting element 6 andcomparative light-emitting element 7 were measured. The measurement wascarried out at room temperature. The results are shown in FIGS. 39 to 42.

Table 8 shows initial values of main characteristics of thelight-emitting elements at a luminance of approximately 1000 cd/m².

TABLE 8 Current External density Current Power quantum Voltage Current(mA/ Chromaticity Luminance efficiency efficiency efficiency (V) (mA)cm²) (x, y) (cd/m²) (cd/A) (lm/W) %) Light-emitting 3.1 0.32 7.9 (0.14,0.12) 830 11 11 11 element 6 Comparative 3.1 0.23 5.8 (0.14, 0.16) 75013 13 11 light-emitting element 7

The above results show that the light-emitting element 6 of oneembodiment of the present invention fabricated in this example has anexternal quantum efficiency higher than 10% and a chromaticity of (0.14,0.12) and that this light-emitting element has high efficiencies andexhibits blue light emission with a high color purity.

FIG. 43 shows emission spectra when current at a current density of 12.5mA/cm² was applied to the light-emitting elements. As shown in FIG. 43 ,the emission spectrum of the light-emitting element 6 has a peak ataround 458 nm, which suggests that the peak was derived from lightemission of ch-1,6chBnfAPrn contained in the light-emitting layer 913.The emission spectrum of the light-emitting element 6 usingch-1,6chBnfAPrn whose benzo[b]naphtho[1,2-d]furan skeleton includes analkyl group has an emission peak wavelength of 459 nm, which is shorterthan the emission peak wavelength (463 nm) of the comparativelight-emitting element 7 using ch-1,6BnfAPrn-02 whosebenzo[b]naphtho[1,2-d]furan skeleton does not include an alkyl group.Furthermore, the emission spectrum of the light-emitting element 6 has ahalf width of 43 nm to be narrower than the emission spectrum of thecomparative light-emitting element 7, whose half width is 46 nm. Theseresults reveal that the light-emitting element 6 of one embodiment ofthe present invention exhibits blue light emission with a high colorpurity.

Next, the results of measuring the chromaticities (x, y) of thelight-emitting element 6 and the comparative light-emitting element 7fabricated in this example with a luminance colorimeter (BM-5Amanufactured by TOPCON CORPORATION) are shown in FIG. 44 . According tothe results shown in FIG. 44 , the chromaticity of the light-emittingelement 6 of one embodiment of the present invention represents deeperblue than that of the comparative light-emitting element 7. This provesthe significant effect of the alkyl group in thebenzo[b]naphtho[1,2-d]furan skeleton in improving chromaticity.Accordingly, an organic compound of one embodiment of the presentinvention and a light-emitting element using the organic compound can besuitably used for blue light-emitting elements for displays, especially4K and 8K displays, for example.

REFERENCE NUMERALS

101: first electrode, 102: second electrode, 103: EL layer, 103 a, 103b: EL layer, 104: charge-generation layer, 111, 111 a, 111 b:hole-injection layer, 112, 112 a, 112 b: hole-transport layer, 113, 113a, 113 b: light-emitting layer, 114, 114 a, 114 b: electron-transportlayer, 115, 115 a, 115 b: electron-injection layer, 201: firstsubstrate, 202: transistor (FET), 203R, 203G, 203B, 203W: light-emittingelement, 204: EL layer, 205: second substrate, 206R, 206G, 206B: colorfilter, 206R′, 206G′, 206B′: color filter, 207: first electrode, 208:second electrode, 209: black layer (black matrix), 210R, 210G:conductive layer, 301: first substrate, 302: pixel portion, 303: drivercircuit portion (source line driver circuit), 304 a, 304 b: drivercircuit portion (gate line driver circuit), 305: sealant, 306: secondsubstrate, 307: lead wiring, 308: FPC, 309: FET, 310: FET, 311: FET,312: FET, 313: first electrode, 314: insulator, 315: EL layer, 316:second electrode, 317: light-emitting element, 318: space, 900:substrate, 901: first electrode, 902: EL layer, 903: second electrode,911: hole-injection layer, 912: hole-transport layer, 913:light-emitting layer, 914: electron-transport layer, 915:electron-injection layer, 4000: lighting device, 4001: substrate, 4002:light-emitting element, 4003: substrate, 4004: first electrode, 4005: ELlayer, 4006: second electrode, 4007: electrode, 4008: electrode, 4009:auxiliary wiring, 4010: insulating layer, 4011: sealing substrate, 4012:sealant, 4013: desiccant, 4015: diffusion plate, 4100: lighting device,4200: lighting device, 4201: substrate, 4202: light-emitting element,4204: first electrode, 4205: EL layer, 4206: second electrode, 4207:electrode, 4208: electrode, 4209: auxiliary wiring, 4210: insulatinglayer, 4211: sealing substrate, 4212: sealant, 4213: barrier film, 4214:planarization film, 4215: diffusion plate, 4300: lighting device, 5101:light, 5102: wheel cover, 5103: door, 5104: display portion, 5105:steering wheel, 5106: gear lever, 5107: seat, 5108: inner rearviewmirror, 7000: housing, 7001: display portion, 7002: second displayportion, 7003: speaker, 7004: LED lamp, 7005: operation key, 7006:connection terminal, 7007: sensor, 7008: microphone, 7009: switch, 7010:infrared port, 7011: recording medium reading portion, 7012: support,7013: earphone, 7014: antenna, 7015: shutter button, 7016: imagereceiving portion, 7018: stand, 7020: camera, 7021: external connectionportion, 7022, 7023: operation button, 7024: connection terminal, 7025:band, 7026: clasp, 7027: icon indicating time, 7028: another icon, 8001:lighting device, 8002: lighting device, 8003: lighting device, 8004:lighting device, 9310: portable information terminal, 9311: displayportion, 9312: display region, 9313: hinge, and 9315: housing.

This application is based on Japanese Patent Application Serial No.2017-091582 filed with Japan Patent Office on May 2, 2017, the entirecontents of which are hereby incorporated by reference.

1. A compound represented by any one of the below formulae:


2. A compound represented by any one of the below formulae:


3. A compound represented by any one of the below formulae:


4. A compound represented by any one of the below formulae: